Spoke too soon on Stig's thread about electrical items letting you down whilst away from home! Not an electrical failure, but likely transmission related?
Symptoms - Major loss of power whereby engine will rev up to 7K or higher, but delivers only 45-50 mph instead of the usual 70 mph at those rpm. Accompanied by whining noise and occasional metallic clatter. Limped the 5 miles home at 30-35 mph!
Suggestions welcome, but I'm guessing it's a strip down of the transmission to check what's amiss? If it turns out to be related to the belt, that would be ironic, given that I only recently posted about my intention to replace it and the rollers at the 10K mark - I'm only about 750 miles off that!