I was driving down a dual carriage way around a bend doing maybe 80-85, when I saw above on a bridge a marked x5 that literally had just finished pulling up, I slowed down instantly, windows were all up etc, what’s the chance of them having a radar gun pointed at me? Do they carry them.

A very slim chance indeed...however, in future the solution is an easy one...slow down...live longer.!

How do you know they had just pulled up?, presumably if you'd seen them actually pulling up, you'd have slowed down earlier?. If they had a radar gun surely they would have come after and stopped you.

Some will carry handheld radar guns, some won't. But if you saw the X5 moving, or it was just stopping, it's unlikely that one of the officers will have been using a gun at that moment, because the motion of the X5 would lead to an inaccurate reading.

Doing 80 - 85 on a bend and either your speed or the curve of the road (or a combination of both) meant that you didn't see the X5 up on a bridge until the last minute?

That does amount to a fairly damaging admission about your driving, I'm afraid.