Initially good news, as the garage have found a plug into the ECU with a bent pin. Drove the car round the M60 (quite quickly!) & around town for two hours without a problem, then it stalled a few hundred yards from home – just as I was about to phone the garage to congratulate them on having found the fault. Bummer. I have had to contact Warren at Topcats Racing to cancel my Monday booking – he sounds almost as unimpressed as I am!