A round file does the job - slowly but surely, opening up the pilot hole to align with the chassis tubes behind:
I was a little more confident on the hole size & position for the offside & drilled a few more holes to speed things up:
Fitted - a little tight for the moment (needs my rubber mallet to remove it) and I pushed it too far in when trying the wheel in place, but good progress:
(I still need to drill through underneath for the locking bolts)