Paul,

One of the guys at my local dealer took a look at it and fitted a spacing washer on the silencer bolt which connects to the pannier frame. It allowed the bolt to hold the silencer a bit tighter with much less movement, which seems to contribute to the swivel exhaust joints working loose. As you say, it's not really up to standard and I will ask for a new retaining spring at the next service. The main thing is, I'm happy I don't need to worry about it on next week's trip to Le Mans for the French GP....