Nice one, I think we may have solved it. All of my input to FSX is via FSUIPC apart from some default views. I found 2 entries, both associated with the brakes, that I had missed when I originally "cleaned" FSX's keyboard controls etc. I've not tested any other a/c yet to see if this has any effect on them but if it has it should be positive surely.
Thanks for your suggestions guys, these issues can be a right &$%^ to sort out but it usually turns out to be someting simple, usually me :blush: