I've changed the Access Mask for Members (see below) but when I login as that member (not my host account) I get no option to attach? is there something I'm doing wrong?
I think the access masks are cached.
I was able to reproduce this. I edited the Member Mask to allow Upload, but no upload visible.
Try to change the Access Mask for the Registered User to something else (Guest Access) save it, then change it back to Member Access, then it should work.
Bbobb already fixed this for 126.96.36.199