Well, still no joy here at the shack.
The old TQ8 file that was prepared by dxbase did successfully upload
to LotW. It did take some time but eventually showed up. Looking at
the results it was fine. 170 records uploaded - all duplicates.
However none of the TQ8 files prepared by DXKeeper seemed to have made
it to LotW. Neither the ones sent from withing DXKeeper or the one
sent manually via the LotW web interface.
Any suggestions - Everything looks OK from my end.