After two months of experimentation, I have finally got a front derailleur fitted and working. I’m not too sure what I did to get it working this time around. I have removed and fitted the same mech a couple of times, probably adjusting things slightly differently each time but finally it has all come together and I’ve got working gears. My best guess for the solution is the routing of the inner cable. The mechanism is one which can be either top or bottom pull and I’ve got a feeling that the way I had fed it through the first time was not quite right.

Whatever, it’s time to stop tinkering.