Bear in mind its not true of all bikes from Nottingham. My '72 Super Course is Nottingham built and has standard threads. ...although I seem to recall reading that the Super Course and higher models were always built with standard threading regardless of when and where they were built.

before the OP goes crazy locating parts it might be a good idea to get out a ruler and count the threads in the BB just to confirm. Doesn't cost anything but 5 minutes time.