Well by golly it passed!! I took it to Shalford Green Garage, Dunsfold (as in the TG test track), because I used to take it to their Shalford branch before it closed... There were a couple of BXs out the front "waiting for parts" - a rear suspension pipe and a door handle of all things! Oh and a lady turned up in a 2CV for new sparkplugs and a sidelight bulb

Proper nice friendly garage.
I was worried about the b pillar/sill rust, but they didn't even mention that. The "past it" down pipe wasn't blowing, and the minor LHM leaks didn't get a mention either. Just two advisories: osf brake hose slightly deteriorated, front brake imbalance 24% (just passed), so that needs a look.
But I'm chuffed!
Booked today and tomorrow off work, fearing the worst, but now I have a free day!
Brian - you aren't around tomorrow are you - fancy meeting up for a cuppa and talking BXs?
Mark.