My escort s1 turbo pulls across the road when not under power,it's had a new rack and ball joints any ideas would be helpful cheers

 

try a geometry allignment

 

It used to be a bit of a common thing with them,mine tracked badly to the left on a certain stretch of road.
As said alignment check and also check the brackets holding the twin antiroll bar set up arent cracked or broken,even that they look in a similar place both sides as that was a cause on another one I owned.
I think there's a company making spares now as I couldn't get them from ford back in 1998 and had them made up in work.
Also big wheels and extensive lowering don't help either,not saying yours is but worth noting.

 

Sounds like tracking / steering alignment. I'm guessing the rack & ball joints were fitted correctly: wheels were straight and the rack & joints set-up as per the originals (as far as possible)? I think that the steering rack would alter lock-to-lock and the steering wheel being straight rather than wandering but if you haven't had the tracking checked then that would be my guess.