Old Sarum "near London"?
It's almost 90 miles from London.
If you're prepared to travel that far each time you want to fly, then Ultimate High at Kemble is about the same distance, specialises in aerobatics and advanced handling, and consistently gets very favourable reviews on Pprune and elsewhere.
White Waltham is a superb club - great atmosphere, best clubhouse in the country, near to London and Alan Cassidy has a superb reputation.
sussexlad makes a good suggestion. The Tiger Club is the longest established specialist aerobatics club in the country with a well-deserved fine reputation. The Club is run by enthusiasts for enthusiasts so very competitively priced. Headcorn is less than 50 miles from London.
FL