Good to know I'm not the only one to have this problem. Now that I've got the wheels on it, discs fitted etc I should be able to work out how much needs to come off to make it work
Hard to tell from the photos, but are you trying to use a post-mount caliper on a flat mount frame with an adaptor, thus would solve all problems buy purchasing a new caliper...?
I've needed to take a file to a couple of different calipers on bikes for the same reason...