if you are not already a member of a club you are unlikely to get a club place - for example, my running club has rules that govern who is eligible for places, and one of the rules is that you must have been a member of the club for at least a year.
have you applied 6 times in a row for London? I know the rules have changed about automatic entry after applying 5 times, but to be honest I am not sure what those rules are - you could contact the organisers to verify that if you feel you should have had automatic entry.
If you look around at all the charities you may find one that doesn't require you to raise an enormous amount. I don't think I would be capable of raising £2K - it is a massive amount
However, London is not the mecca of marathons - Paris is fairly easy to get into. You are being a bit sensitive about the replies!