Can anyone tell me if the FG steering wheel and column will mechanically fit into a BA?

Mechanically, IIRC they fit up the same.

electrically you will need to make a patch loom from the back of the FG column (FG ignitition wires plugged right onto the back of the Switch, BA had a short loom fitted on the column) to where the Plug is on the dash loom of a BA.

Thanks very much, that was all that I needed to know