Have a look at the photo on this link Robby, if it looks like the worn sprocket the only long term cure is to replace it.

http://www.talkmorgan.com/ubbthreads.php/topics/238117/7

Cleaning and silicone spray will help but only for a few miles. Both the alloy sprockets I have replaced have only lasted 3 or 4 thousand miles. Hopefully the current steel one I have fitted will last much longer. If I was buying a new one the Supermax looks to be the best way to go and value.