Thanks for your replies!
Yes, it was the actual Nikon repair centre at Nikon House in Kingston, which is where the training day was. I pulled out my flash in the class and saw that the panel was not there, showed the instructor who booked it into the repair centre for me. It had really obviously just fallen off, as there was no dust or anything underneath, and I've hardly used it, so really don't see how it could have been damage.
Yes, I have signed up for a course at our local adult learning college - 10 evenings a week for £140! It's a not for profit college. To be honest I've just bought a load of really good books which I am enjoying working through too, much cheaper than day courses. It's hard for me to get the time off to do the courses I am studying law, look after my 2 year old daughter full-time and I help with my husband's business
. That's another reason I was a bit annoyed with the Nikon course - just the loss of a day's freedom!
Oh, and when I spoke to the guy who took the course he said they didn't expect people with d40s or d60s to know mcuh about photography - I know it's an entry-level camera but give your customers some credit!