There is the NLSMEE which meets in Finchley just above the North Circular from memory but has its track up near St Albans (that used to be in Barnet years ago) and further east there is a club at Chingford. To the north west is Harrow & Wembley and also Northolt MRC which is not just small stuff despite not having 'engineering' in its name.
Outside the M25 there is St Albans & District MES which is highly recommended by a regular participant of this forum and has very reasonable membership fees,
plus you can go along to a meeting to see what it is like without joining or having made a model and even get a free biscuit with your free coffee.
If you are already in central London of an evening and your tube ticket is flexible you could look at going to the SMEE although it is south of the river.
Edited By Bazyle on 31/05/2018 12:47:55