I have an ahg one spare, I'd take 25 quid plus postage for it. Its in good nick, bout 3 years old, stored unwound. I got hold of one of those screwdriver ones on ebay for cheap (thanks to a mis spelling when it was posted lol) and I DO think they're a better job than the anschutz ones, and i can get mine calibrated at the local plane making facility (what doesn't everyone have one?) that said if you just want to get the same every time then ahg is prob plenty good enuff, its here if you want it.
Kind regards, Rob