Mike,
I'll take a look when the wind dies down a bit tomorrow. Can't get the cover off the car without it taking me into the next street just now!
New P/S and alternator belts were fitted before we went off to Spain and I kept the old ones as spares. Part number is either 054 903 137 (11.0 x 866) or 035 260 849C (12.5/13 x 992); the garage didn't identify which one is which.
Chris.