Well she passed her MOT with flying colours, and on the way home, the brake servo stopped working
On closer inspection, I found that the servo pipe had collapsed internally, so my initial search was to GSF in Apsley, who unsurprisingly don't stock them anymore

On my way home from work, I popped into Wendover motor spares, and picked up new HT leads, plugs, oil/air/fuel filters, dizzy cap and rotor arm, along with a length of servo hose, which I cut to fit, and hey presto........brakes again
I also did the service, and found that 2 of the 3 bolts that hold the base of the air filter were kapput, so it's either locktite or a new tap
looking forward to putting a few more miles on her, and I hope Dai gets back soon, as I've got to do something about the ride quality
