Hi Darren.... Just read through all the events of the last few days.... Sorry I missed the "fun!"
I would think from passed experience that there may be a hydraulic fluid deficiency in the left hand brake test roller? ( it was the left that was slow rising?)
I have seen this before when I worked in Mold (random town name!) The seal in one of the rollers hydraulic units (like a slave cylinder) was worn in it's bore and allowing fluid (brake fluid actually) to seep past it, completely screwing up the figures..... We figured it out when 3 cars had the same results!!!
You only have them calibrated once a year.... Like an MOT, time of test and all that!
Remember your brake cylinder could fail at any time in the year between tests couldn't it? You would realise the cylinder could fail at any time and therefore if you caused damage to something like a car/wall etc you would probably try and sort it out the best you could without being out of pocket? (insurance excess etc)
As it is the garage caused you stress and a 200 note bill.... you could possibly reclaim much of this without resorting to the "headmaster!"
Maybe a quiet word with the test station might help? they might service your motor or something as compo... Good luck getting cash out of them!
I never told you this but... If the tester doubts his rollers he can use the decelerometer in an emergency situation i.e. the rollers fail and he has cars booked in, he has to notify VOSA and the repair guys for the rollers etc.... From memory he has a few days that this can be used for to get the rollers repaired then he has to stop testing till repairs are made to satisfaction..... At least that is how it used to be, well that's how we did it anywho.
Reason for the line I take.....
VOSA (used to be the MOT) by the way are a bunch of B45ta£&s and I would not trust them as far as I could throw anyone of there "experts".
Idiots nearly lost me my job because of a "misinterpretation" of the wording about orange and white light in an indicator of all things.... Sounds minor but when the testers "pionts system" allows you 80 before you are struck off and they decide that 20 are issued for a "mis-fail" the 4 indicators that had pealed the orange paint off them due to heat over time and use, meaning that they where showing 1/2 white light in the upper part of the lens that I failed and they overturned meaning I got 80 points for 1 test!!!!!
Then I had to go for re-training (after a small "sign to admit guilt" or face a crown court thing

Yes, it's classed as a fraud case against the public! Obtaining money through deception. Since you are classed as a civil servant you're up for a slap if you don't take it on the chin and re-train. (I have no idea who wrote these rules!)
anyway... I went to the re-training and was told in the "tell me what you did to be the naughty boy I see before me" bit of the re-training that it was ridiculous and that ANY white light from an indicator was an instant fail, be it from a cracked orange lens or a peeling bulb!!!!
The gem of it was...... Because you had to sign the "admission of guilt" papers before the re-training I couldn't get the damn thing overturned and VOSA were fully protected against any fight I could muster. As said..... Bas7$£ds

Slightly

But you started me off!
Just might be the issue? ... The hydraulics in the roller system that is..... Not your indicators!

Glad you got the motor sorted in the end..... Quite an epic battle..... I must post a bit about my new motor sometime..... You'll love that.... Already cost me 300 notes and 2 days off the road.... Oh, and a replacement cylinder head
A story for another day I think..... I've got about 300 pages to read to catch up!!
Ralph.