John,
Fortunately the guys who installed our mot bay told us about the spring problem which is due to lack of grease. We still had to do it ourselves afterwards. Our brake tester had class 7 software on a class four bay and they wouldn't believe us despite having readings of 600kg per wheel on a citroen ZX! That's what happens when reputable firms farm stuff out to the lowest bidder.

If it's any use to anyone, we bought a bosch emissions tester from Joe at Celtech and the after sales has been brilliant.

Cheers,
Richard