Thanks for all the info folks. Much appreciated.
I should say that the drift doesn't appear to affect my final images. The still stack np, I just have to crop the image a bit after stretching. Its more an annoyance than anything.
I've also taken a bit closer look during an 'animation' and the general direction is S/W but there are the odd frames where the drift is only S and others only W.
John that is how I used to guide exclusively, star diagonal and guide camera. It always worked a treat for me. I can't remember why i changed. Probably because I put a flip mirror into the equation.
Paul, yes I'll check on my PA. I was very confident when I first set the AP up, but found I had to tweek it a couple of weeks later. Settling ?
But another check certainly won't hurt. I'll persevere a bit before going the OAG route. Tried it when I first started imaging and swore I'd never go back there. Though I've learnt a thing or two since then.
Yes i saw that David. I still shudder.
I'll look into another guide prog Peter. The AP came with Pulse Guide but I've not loaded it as I've always been happy with phd. Just another new thing to learn. Oh and i use either the latest Maxim or M4.5 (depending on the night, still not a big fan of the new camera control interface compared to the old one)
Plenty of food for thought, thanks everyone.