Deleted entries as detailed above, no good.
Uninstalled DAQF, searched all registry entries for Azeotech and DAQF and deleted except for multiple entries in:
UserSettings\S-1-5-21-..........\Device\HardiskVolume..... (warning about disk issues).
Deleted any folders/files on local PC related to AzeroTehc or DAQF.
Re-started PC to flush any memory resident data.
Reinstalled DAQFv19.1, now have the defaut 25-day trial grace period development licence (instead of needing to use my developent USB dongle) and still table editors text font is tiny.
You mentioned that I may have inadvertently set the font size to small in preferences; this can't be the case now? The only preferences referencing font size I can find are table font size and sequence editor font size and these are the default 8-points and 10-points resectively.