Ok, just a wee problem.
Whe I was driving my robot around something really awfull happened again, again and again.
I drove my robot round for a minute and then suddenly it jolts forward and goes out of control randomly driving around, do I jumped on it and yanked the link out.l
This happened 5 times.
We (me and bodge job) lookedd at the wiring and everything was ok.
Don't know what the problemo is.