Any question answered...

Not sure I understand the problem, the FD should have been initially set up with the chain on the inner ring anyway - If that makes sense.

Start again. Make sure the shifter has released all the gear cable, set the L limit screw on the FD so that the chain doesn't slip off the ring into the BB cluster, but also doesn't rub the FD cage when in the largest rear sprocket.

Once the L limit screw is set, pull the gear cable taut and tighten the cable clamp. You'll probably then need to tighten the slack using the downtube mount/guide.

Pifko - yes. I did that several times and came up with the same answer each time - still doesn't work. :(

Which Campag FD? Which shifters?
What frame is it? Some oversized seat tubes can push the FD mounting outwards by enough to make it impossible to shift onto the inner ring. Modern FDs are built to account for big tubes, but an old one would have been designed on the assumption that all seat tubes were 28.6mm dia. That's the only authentic compatibility issue, and would only occur if you have a braze on FD, obviously. If that is not the case, you're doing something wrong.
A new SRAM Rival FD can be had for £21 (less if you need a 31.8 clamp on one, as I've got one going spare), so you should be able to get up and running without too much expense.

The levers are Campag Xenon 10speed - everything else is Campag - except for the SRAM cranks (GF has short legs and needs 165s). I think you may have hit the nail on the head though - back to basics. Upon further inspection the FD doesn't appear to be Campag but a generic one. That must be the issue.

Let me dig out the calipers. I think I will throw money at this problem....

Thanks very much for the answers peeps. This is such a useful thread.