re: go ahead.
Not in the UK. We have to say "pass your message". I think it may be something to do with the words "go ahead". They sound a bit like an instruction or even a clearance to move forward, so the CAA decided to make our phrase; "pass your message".
I know, I know, it sounds fine to me to, but once upon a time I'm sure someone got the wrong end of the stick and felt the long arm of the law.
Traaaaaaaaaaaa.