Most of these problems seem to occur in the Northern Ireland registry which I think was imported at some stage. This person has no surname and no forename and was born in the (default) Jan 1900:
I note that there is an appointment form 296 signed on 30-Nov-2004, appointing Mr Thomas John Smith DONNELL, but with no appointment date on the form and no date of birth. The signature date matches the appointment date of the unnamed person. I suspect that in a database merge, the date column was filled by his name, leaving the name columns empty.
I can't find any resignation form though.