iirc not being able to drive straight onto the ramps is an immediate fail, but as said some may let it slide.
we'd fail you if you couldnt get on the ramp (or get the sliding jack under the car to lift it up for the inspection since the mot ramp has to be a drive on ramp) or on the rollers, the brake efficenty rollers are pretty deep set into the ground, think dean (bio hazard) at the rolling road irrc his sub frame hit the rollers.
only other thing you might run into is the head light aim, if the cars too low they may aim to low, same way if you raise the coils up over standard height they might aim too high. had a car come in and it failed initially on the head light aim being too low, then we saw it had 4 broken coil springs-oops.