This chapel is situated on Mount Sion, near the range of buildings called Sion Crescent, and in the immediate vicinity of the Grove. It was built by voluntary subscriptions, and opened for divine service on the first of August, 1720, for the use of the presbyterians; on which occasion the Rev. John Archer officiated.

In the year 1731, the Rev. Thomas Bayes, F.R.S. appears to have been the stated pastor: how long he continued is not known; but his decease took place on the 17th April, 1761, when he was fifty-nine years of age. Mr. Bayes was a man of considerable literary attainments, and of good private fortune. … Mr. Bayes bequeathed his valuable library to his successor, the Rev. William Johnston, A. M., who became the stated minister of the chapel, in the year 1752.

Mr. Johnston was a native of Scotland, and was distinguished both by his literary acquirements and his amiable and gentlemanly deportment. During the season some of the nobility and gentry attended his ministry, amongst whom the Duke of Leeds was an occasional hearer. The chapel in general was well filled, and Mr. Johnston lived in the affection and respect of his people. His remains are interred in Speldhurst churchyard, with those of six of his children.

For some time after the death of Mr. Johnston, there was no stated minister, but the chapel was opened for public worship for about five months in the visiting season. The next minister was Mr. Skinner, who afterwards removed to Cranbrook. He was the first master of the Free School at Southborough. Mr. Skinner was succeeded by Mr. Hampson. Mr. Hampson was followed by Mr. Gough in 1795, who was also master of the Free School at Southborough. From this time, in common with many of the old presbyterian places in England, the congregation gradually decreased and dwindled away until the chapel was nearly deserted. The Wesleyan Methodists were allowed to hold their meetings for public worship here for some time, till they erected a chapel for themselves in Vale Royal, in the year 1812. Mount Sion chapel was eventually closed in the year 1814, and thus it remained year after year in a decaying and dilapidated condition, exhibiting a melancholy proof of the desertion of this once crowded sanctuary, and of the decay of presbyterian vigour and piety.

In the spring of the year 1830, the attention of Thomas Wilson, Esq. of Highbury, then on a visit at the Wells, was directed to this place of worship. After making arrangements with the surviving trustees to apply the chapel to the use of the Congregational body - commonly called Independents - Mr. Wilson undertook to have it thoroughly repaired. … The Chapel was re-opened on the 8th of July, 1830. The Rev. John Clayton, Jun. of London, preached in the morning; and the Rev. James Stratten of Paddington preached in the evening. Mr. Stratten supplied the pulpit for the four following sabbath days. The Rev. Benjamin Slight, the present minister, formerly of Highbury College, preached his first sermon in this chapel on the 8th August, 1830. On the 10th of December following, a church was formed on Congregational principles; on which occasion the Rev. Thomas Jones of Woolwich presided. At a subsequent meeting of the members, held on the 21st January, 1831, it was unanimously resolved that the Rev. B. Slight should become the stated pastor; and on the 10th of May following he was publicly set apart to the office.

Benjamin was confirmed in his post when Dr. Henderson of Highbury College read a letter of acceptance in March and his public ordination took place on 10 May 1831 in Mount Sion Chapel at 10.30 a.m., the ordination prayer being read by Rev. J. Slatterie of Chatham in the presence of Rev. A. S. Dubourg of Marden, Rev. R. Halley of Highbury College, Rev. John Clayton M.A. and Rev. E. Jenkins of Maidstone. In the evening, the service was led by Rev. J. Stratten of Paddington.

Between the two devotions, a "plain dinner" took place at the prestigious Sussex Hotel (along the famous Pantiles, at no great distance from Little Mount Sion), those attending paying 3/- per head. Two years before, the Duchess of Kent and her daughter Princess (later Queen) Victoria had lunched there and would stay the night there in 1834.

Services were held on Sundays at 11.00 a.m. and 6.30 p.m., prayer meetings on Mondays at 7.00 p.m. and lectures on Wednesdays at 7.00 p.m. The school room was separated from the church by sliding shutters and could seat 50 persons, the church itself seating 400. During the week, it was used by a girls' school (60 girls) belonging to the British and Foreign Schools Society.

A "violent cold" was sweeping through the congregation towards the end of June 1831 and having a marked effect on attendances at the Chapel. Benjamin arranged to take time off at the beginning of August for relaxation including some time by the sea.

Benjamin ran Bible Classes from October 1831 which were both novel for their time and popular and also founded a library for the Sunday School early in 1833. A school was founded on Friday 9 October for illiterate servants (presumably female) and other young women and began with a dozen pupils. The syllabus included principles of simple accounting.

The Rev. SLIGHT was granted, at his own insistence, one month to six weeks holiday each year for 'recreation and visiting friends'. Benjamin wrote to Thomas Wilson on 21 June 1831 concerning the possibility of an annual anniversary in July or August at which a collection could be taken for his benefit. He said:

"It seems desirable that there should be something of the kind - as the expenses of a minister here, who must appear respectable in such a place, are much greater than in most others. And every Minister requires books."

However, some members of the church expressed dissatisfaction with the way in which the church funds were being spent. Benjamin explained, in his defence, that his salary was not fixed and his only income came from pew rents (280 from the chapel's capacity of 450 seatings), visitors donations and surplus money from collections.

At Mount Sion, consideration was being given in 1841 to the building of a new church in more salubrious surroundings (mentioned in a letter of 29 July of that year from Benjamin SLIGHT to Joshua Wilson). This had been precipitated by the conversion of Wilmot Lodge, the house immediately below Mount Sion chapel, to a 'beer shop or common public house' and a deterioration in the condition of the surrounding property and the respectability of the neighbourhood generally. Moreover, the chapel's situation at the top of a steep bank away from the main thoroughfares was inconvenient. A meeting was held in June of that year where it was agreed that "the erection of a new place of worship in a more eligible situation is a desirable object." Some difficulties caused the plan to be delayed until October 1843 when a private meeting and, on 23rd, a meeting of the congregation met to discuss "a renewed effort for obtaining a New Chapel". The site chosen, in Mount Pleasant, a fashionable area adjoining the development of the Calverley Estate, was close to the newly built District Church (now Holy Trinity) and was donated by the Rev. SLIGHT, having cost him £348.

Handbills and subscription agreement forms were sent out on 1 November 1843. The foundation stone was laid on 21 May 1846 (or 1845?) by Charles Hindley M.P., prayers being offered by Rev. Dr. Borner and an address by Rev. John Clayton M.A. The opening of the elegant, classical new chapel which cost £3,800, took place on 20 January 1848 (the impressive Doric portico was not added until 1866). There were services in the morning and evening that day and a mid-day dinner at the Sussex Hotel on the Pantiles for visiting ministers and friends. Rev. W. Pawling of Lenham, Rev. E. Jinkings (Jenkins?) of Maidstone and Rev. J. Hedgcock of Marden participated in the services. Rev. John Harris D.D., President of Cheshunt College preached the morning sermon and in the evening, Rev. John Leifchild D.D. of London. Dedicatory services throughout the following week were disrupted by cold weather and the lack of heating. However, Rev. H. J. Bevis of Ramsgate preached on Sunday 23rd and, a few days later, on 27th, Rev. Samuel Martin preached to the young people at the final dedicatory service.

On 23 June 1849, the Queen and Prince Albert paid a surprise visit to her aunt, Queen Adelaide, at the Calverley Hotel (formerly Calverley or Mount Pleasant House), not far from Mount Pleasant Church and on the opposite diagonal corner of Calverley Park from the SLIGHTs' house in Park View.