1. I lived in a car in London for 6 months. It was pretty fine. McDonalds was my washroom.
2. These boats are rare. I mean really rare. This is not the norm. The boats and the moorings are damn expensive so this doesn't make sense even for the landlords. Even crappy moorings cost.
3. You can go to the council and get a bedsit if you're in this situation. Literally the next day. Might have to share with a crackhead for a week but that's life.
4. There are plenty of other places to go in the UK where the salary/housing cost ratio isn't crazy. I lived in Nottingham for a bit and had a 5 bedroom detached house in a nice bit for £500/month. £230/month will get you a 2 bed flat better than this.
This is a sob story - nothing more.