Thanks guys. Looks like the general problem is a form issue. Makes perfect sense. I am conscious of trying to maintain consistent form. I try to have the string touch the centre of my nose and tuck my thumb under my jaw. Perhaps I am getting some inconsistancy each time I strap on the release aid and that is adjusting the distance I have to reach for the trigger? All this gives me something to work with anyway. I'm now pretty sure it isn't equipment related. Good to hear that a few of you have the same sort of offset in your pins too.