Yeah, I do have an old BB, but old is what it is and the threads are not clean! I'll try and clean them up and test it. It may confirm which threads are off.
I could always take it back to the shop that removed the old BB for me. They charged me enough for it!
Hm that's strange. Do you have an old BB lying around to test if that goes in straight? As you don't want to go to a shop.