Beware Webuyanycar. Firstly as you say they offer peanuts. Second if you take their offer up. They direct you to one of their agents. From my source it was Carcraft (or something like that) nr Lakeside, Essex.
Once there they go over your car and judge it by Rolls Royce Concours standards. Flyspeck here....dust there...those wheelnuts not in alignment etc. Then after making you wait about SIX hours offer you about 20 to 25% less than the previous offer to cover these imagined defects.
The staff get commission on the amount they 'save' by screwing you.
By this time (several hours) your tired, hungry maybe the kids are screaming and you just want out. So you take the derisory offer. Then there's the £149 fee (for something or other).
Either way ..it's a con.
Spend the £50 put it in Autotrader. If you can't be bothered use
http://www.sure-sell.info/ Honest John from the Telegraph recommends them.