Possibly the degree of wear of the rear sprocket has something to do with the amount of "squeak" from the belt. There comes a point when Mr Sheen etc. cannot keep things quiet for more than a mile or two and a new sprocket is the only real cure. Hopefully this will all become another problem of the past if the steel sprocket is the cure for the excessive wear rate of the current alloy sprockets. A prematurely worn sprocket that has only lasted a few thousand miles should be a warranty replacement, in my view. Will Morgan try and make it another upgrade that the owner can choose to have, at a cost?