Hi Bruce and Joe,
Pleased to be able to post that I have been able to source a drum and sprocket set (separate pieces as shown in Bruce's diagram) so all is now well. I note that these would have been supplied with the saw originally, so if the situation re-arises I need only replace the sprocket. However I shall be carrying out careful maintenence as indicated by Grumpy (unlike the previous owner).
Thank you again.
