Took the mirror cell apart and I've managed a 15mm forward position of the primary. I had to replace the existing collimation screws, M5x20, with M5x40. I also added M5 connector nuts to get the 15mm spacing and with an M5 washer(so could be 16mm forward) was able to use the existing springs. Just a shame I couldn't use the existing locking screws. And it's all undoable! Collimated nicely and raring to go. *IF* we get something close to a clear sky I can test focus. Should it prove too much