Brilliant reply (as always, it seems!), thanks for that Pete.

I'm trying to get details of when they're having problems - unfortunately since they're on the other side of the country I have to rely on this information being sent to me separately, and I don't have enough to draw any conclusions yet.

I'm continuing to gather data from both ends, so I'll give it a few more days and see if we can get a better idea of when they're having problems.

Once again, thanks for the quick and detailed reply - the best software support I've ever come across!

Chris.