Either your caliper isn't centred properly or, more likely, the wheel isn't dished properly and the rim is offset to one side. What did you use to make sure the rim is central on the hub?
Thanks for all the input. A nice weekend job now the sun’s out to re-check everything.
I suspect everything has bedded in and I should have spent more time making sure the spokes were sitting properly in the flange and the nipples in the rim.
Either your caliper isn't centred properly or, more likely, the wheel isn't dished properly and the rim is offset to one side. What did you use to make sure the rim is central on the hub?