By 1783 John was doing so well that he was able to buy a 24-year lease on two houses—no. 12 (later no. 28) Leicester Fields (later Leicester Square) was one of a terrace of large Georgian houses forming the east side of the square, and its garden backed on to that of a smaller house, no. 13 Castle Street (now Charing Cross Road). John set about transforming them with gusto making many alterations to both houses, meanwhile the family remained in Jermyn Street and of course Earl's Court. The works lasted until 1785 and cost over £3,000. An extra floor was added to the Leicester Fields house and tall new chimneys rose high above the street. A large ‘conversazione room’ and lecture theatre were built to the rear of the Castle Street house with a Museum above, and its basement was extended to provide an underground stable. Despite the building works, both houses were quickly put to use, as in the autumn of 1783 John advertised a lecture: ‘On Monday evening 6th October at Seven o'clock Mr JOHN HUNTER at no. 13, Castle Street […] Tickets at his house No. 12 Leicester fields or at 42 Jermyn Street’.

Anne's social life was looking up. On 30 June 1784 Horace Walpole escorted her and John together with Lord and Lady Herries around his house, Strawberry Hill in Twickenham. Something of the warmth of the Hunters’ friendships can be gathered from the invitation that John sent to William Eden to watch the first balloon ascent by an Englishman on 16 October 1784 by his anatomist colleague John Sheldon and Jean- Pierre Blanchard:

And in a letter a few years later to Edward Jenner after the birth of Jenner's son, John wrote: