Mortgage/ rent/ service charge free: Off grid?

wall1

I've built some equity in my first London flat but struggling to find a freehold in the not particularly desirable area in my budget. I don't mind paying a bank the interest on a mortgage but service charges and ground rent to me are dead money and moreover exploitative. I'm now at the point where I'd rather clean out my own excitement than fund an offshore freehold owner. Work will be a few days a week in town so any inconvenience of a long commute is lessened but would I just be better off on a barge on on the Thames or its tributaries?