This only started to happen when I created a new file and imported the entirety of the old mdb into this new file. The only reason I did this was because I had read some article about minimising the possibility of corruption and the advice included turning off the name Autocorrect as it was buggy. The old file had been created without turning it off and the advice was to create a new file, turn of autocorrect and then import all objects.
So go figure - advice to minimise corruption actually left me with a corrupted db! Granted this advice didn't mention if it was for Access 2003 (the apparent bugs may have been fixed) so maybe I should have ignored it!
Has anyone else heard anything about the name autocorrect causing problems that warrant its turning off?