Well I've done it, had a new chain and sprockets fitted. Now it feels like I have a new bike, what a difference. It is so much quieter and there is no snatching whilst going along slowly or coming out of corners.
I have also copied the idea of using a bit of plant pot to extend the chain guard, I heated it up to mould it up to the inside of the guard and then almost flattened out the rest to hang over another few inches. So now the back left of the bike is staying clean.
Good results all round.
cheers blokes