Engine mount nothing to do with MOT at all ,could advise it only if he was picky.The ARB drop links certainly are though!See here - http://www.motuk.co.uk/manual_240.htm
Section G part 3g is the relevant bit for the ARB drop links.
Engine mountings simply not covered at all - quote
" . With the vehicle over a pit or on a raised hoist, check the vehicle structure for any fracture, damage or corrosion, not within the prescribed areas, which is likely to affect prejudicially the correct functioning of the braking system or the steering gear, "
Nothing to do with brakes or steering ,nor is its failure likely to affect them.Might make the car feel a bit unpleasant though!
Some MOT testers are highly zealous people ,mainly those at main dealers or fast fit centers ,in my experience!
The best testers to go for are those that do a lot of Motor Trade work - they will generally be realistic and will conduct a fair test , not failing unneccessary items .