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.