My Bug bear is that some are willing to part with £2000 to be told how to clean an oven, ok some things yo need to go on a course for i.e. carpet cleaning, leather repair etc, but surely with a little common sense you could figure it out, and most courses arent going to cover every oven or cooker you come across.
It would be cheaper to get a professional oven firm in and watch what they do, might not seem ethical but far more value for money!
steve