Some of the main marinas
in London are... Poplar dock
, lime house, st. Katherine Dock
, South Dock. That's all I can think of for now.
If you want to live aboard, poplar and lime house are both about £10,000 for a year and south dock is cheaper but has a 2 year waiting list. It also depends on how flashy your boat is - I've encountered a lot of yacht snobbery in London. Marinas
don't want grubby, 'well loved' boats spoiling the view!
Or you could keep her in Portsmouth. We have kept our family
boats in Haslar marina (1hr 40 train from waterloo) or anywhere in Southampton
Hope this helps your decision making!