So I've been pulling my hair out over this thinking I've been doing something wrong, and it turns out it wasn't me at all, the new flywheel I was fitting had issues, the holes in the centre for the dowels were too small, this meant that when tightening up the flywheel it was actually pushing 2 of the dowels into the crank as far as they would go and then stopping, when torqued up you could barely notice anything wrong but in actual fact the gap between the crank and flywheel was about 4mm, which was leaving a pathway for oil to come out, I was given another flywheel to try by gsf but that was the same, ended up fitting my old flywheel back on with new seals and she's now bone dry!!
Moral of the story is.. stay away from gsf for major parts! I got a full refund but it's cost me 2-3 days off messing around, and done my nut in!!!