Thanks Ken. I will try fine tuning using Frame and Focus next time. The other night NGC 604 ended up being circled - and it had something like 11 x 11 next to it. I assume that I should be reducing the minimum star size to try to exclude it?
I have read the manual about setting up the rig and I think I have the step size and things like that well sorted out. I have had no issues with other objects.