Cheers brother for the sage advice. It turned out that a couple of the rear sprocket carrier pins were loose also (advice from another poster) and the front sprocket retainer plate was shagged too. All in all an accident waiting to happen. A delayed disaster in plain view but thankfully all sorted now. Cheers again. Kenny.
Hi, just to let you know that I sent another email to Grenoble asking Pierre if he could chase the refund up. I've just had notification from PayPal that the money has been refunded. Success then, though it took a while.