Thanks for the various suggestions above - much appreciated. As you say, it seems like quite an expensive fix although I guess its a one time cost - I found something in the US as well at about half the price but not sure if they ship here so...

Hi, Have not replaced it yet. Have some other priorities at the moment. The exhaust from Demand Engineering Ltd look really good

JAMB, Have you replaced the exhaust yet? Which brand did you go for and what are your thoughts so far??