Annoyingly, my forms were now taking an age to load. As soon as I loaded it the first time I remembered that this was a problem I had come across before and had discovered the solution. A bit of brain-wracking didn't help (it just hurt). In these situations I say (if you have the time) to do something else and leave the problem floating around in the back of your mind and in the normal course of events, you might remember what it was. Normally, for me, this is either:
- when I leave the house (which isn't very often)
- when I'm sitting on the loo or in the bath
- when I've gone to bed
Tools menu -> Options -> General tab page -> Name AutoCorrect. Uncheck Track name AutoCorrect info.
Voila! Decent speed in complex form opening.