Hi all. Just thought I'd take the opportunity to report back on my cambelt change.
This was well overdue (lack of available funds) at 6 years since new Vauxhall replacement engine fitted.

I took it up to see Daz on saturday and perched myself on his shoulder to 'look and learn'.
Two things worth a mention here:
1, the old belt was in quite good condition
2, the left bank timing was out (right was ok), not by a lot but still disappointing I thought as it was untouched since it left the factory
Just to embarrass Daz, I feel that I must say that it was a pleasure to watch such a meticulous job. It was also good to have the finer points explained as the job progressed, by somebody who clearly understood all that the service entailed.
To anybody who has not met or had any work done by Daz, I cannot recommend him or his work highly enough, and he is a thoroughly nice, helpful chap to boot (I'll collect the cheque later Daz)
To be honest, although the engine runs very well, I haven't noticed a startling improvement in either performance or economy, although my average mpg does look to have climbed from 28 to around 31mpg over 300-400 miles since Darth worked his magic, but it is difficult to be sure that I am comparing on a level playing field so I will monitor over next couple of weeks and report back.
Thanks again Daz for all of your help.