E-Drums are ridiculously expensive so even second hand I think you'll be extremely lucky to get anything better than the most utterly basic "designed for kids" starter kit like a original Roland HD-1/HD-3 or, if you are extremely lucky, maybe a TD-3 if no-one else see's it on eBay, and I would be amazed if you find one with a double bass pedal at that price range so make sure when you read the advert than includes the pedal and stool or you'll need to add upto another £50-100 for those two combined.
I've had a Roland TD-3 (mesh snare, rubber toms), upgraded to a TD-6 (all mesh) before finally upgrading to a custom setup of Jobeky Mesh drums with TD-12 brain so I tend to stick with Roland, but the Yamaha stuff is OK too. I'd avoid the original Roland HD-1/HD-3 kits which are extremely limited, even for beginners and, to me at least, more suited to allowing a younger child with maybe a passing interest to have a bash whilst the Roland TD-1/TD-3 are a better "starter" kit for an adult.
Personally I'd be looking at spending £350-400, which is a lot more money than your budget I know but it gets you a "better suited to adults" starter kit on eBay via "Buy It Nows". There's a
TD-1DMK kit (all mesh drums, no pedal, no stool) for £350, or a
TD-3 kit (only mesh snare, single bass pedal, stool etc) for £375 or a
TD-1DMK (all mesh drums, single pedal but no stool) for £400 which are all reasonable starter kits. There's some Yamaha ones too but I don't know enough about them to give a recommendation.
So, TL

R - E-Drums are stupidly expensive vs acoustic, so prepare your wallet!