If you get on well with your parents I don't see why you should rush to move out.
Continue paying £50 a week IF you are on a low wage or are desperately saving for somewhere to live.
Pay ALOT MORE TO THEM if you ride a fancy bike and drive a powerful hatchback.
They shouldn't be subsidising your lifestyle.
I know someone who was in this situation and milked it. They'll be paying for your council tax (yes they will) as well as your other associated costs that are more than you put in. Feel embarrased?
If my roof over my head, food and bills all came to £200 a month I'd know there was someone paying out of their pocket. You are riding their goodwill.
Pay them £100 a week. They may protest but be a man and insist. Don't be a parasitical child.
Shag' just noticed your post above. If you are in straightened circumstances its different to what I posted here. You aren't taking advantage of your mum. Theres a distinction.