Thanks for the responses!

I guess £150 is pushing it a bit, from the sounds of things... I'll have a look for some wheelchair motors though and the like, off for a scrapyard visit soon to try and find some parts!

What sort of technical fault too, if you don't mind me asking? Just interested for planning ahead with what could go wrong with mine! Glad to hear you pulled it off though, does sound a good way to do it with a wheelchair chassis - Might have a look on Ebay, see if I can spot anything on there too! Thanks!