Car failed its MOT last week on this:

Repair immediately (major defects):
•Offside Front Lower Suspension arm pin or bush excessively worn rear bush rear arm (5.3.4 (a) (i))

Now is it the rear bush on the rear arm or the front lower arm bush?

How much work is involved in replacing this as the local guy who does all our servicing seems to be a bit worried about jacking the car up to do the repair as there is potentially an issue with the suspension (its down at the front). I suspect that a ride height sensor has been knocked or damaged causing the suspension problem.

Any ideas / approx. costs to fix this?

Front lower suspension arms are easy, just remember to tighten the bush bolts back up with the vehicle on the wheels, ramp or pit useful for this , i did both on mine myself a few weeks ago , took around 40 minutes a side

Rear bub bushes are OK to do when you have done a few and have the tool to press out the old bush in Situ , you will need a 4 wheel align afterwards .

Parts from Duckworths of course !

Update.
Went in again on Monday and passed!!

Great news!  Formerly happymadison1978