Sorry about this, I am waiting for my server host to properly switch the domains back around, at which point the .com will properly redirect to the .co.UK and logging in will be fine. Meanwhile best to just use the .co.UK
I'm so sorry this has caused such problems, it never occurred to me there might be legal issues with my choice of .com If we hadn't been made to switch back then we wouldn't be having these login problems.
I should know later today what .com domain we can use. Good thing I treated myself to a scratchcard yesterday when I was feeling a bit blue about it all... I won a tenner which is enough to buy another domain