I want to clean up my Phones table as there are multiple old categories - they have no recognised constituents sitting within them but just various numbers of ‘Blank ID’ lists. Until I have removed these Blank ID's to make the record empty, I can't run the tidy tables plug in. How can I find out what these Blank ID's relate to? I have tried running a query to locate them but it only found 6 constituents so there are clearly many more somewhere else. Had anybody come across this before?