cool cheers dude. looked a little on the internet about what speed controllers do and how. my old man is going to speak with his mates at work for me about making my own. he works in electronics, they make sensors and controllers for industry so might and probably will sort it for me... fingers crossed!
i looked at others and noticed they all seem to use much smaller motors than what i have (coincidentally off an upgraded machine at my dads workplace) . What makes my idea even harder is getting 4 wheel drive (via belt), whilst still making a works both ways up one. if that makes sense. im pretty sure im going to need custom electronics, but im going to look into those servo controllers that you mentioned. will they be up to the job?

Cheers
Chris