Hi -- been out shopping with DD this afternoon so not looked at the thread for a while. To answer a few points people have raised:
Qualifications 18 years ago: none were asked for apart from volunteering to do it and the initial training for lay inspectors (who were at that time as someone has suggested, intended to look at aspects of the school other than teaching) was farcically bad, the poorest anyone on it (from a very wide range of backgrounds had ever experienced). My own background in case anyone's interested was publishing. After (I think) two years Ofsted made the decision (which we lay inspectors greeted with initial trepidation) to have us judge teaching and we then had initial training in this and have subsequently done all training and grading exactly as our ex-teacher colleagues. I should add that the training has definitely never been as dire and pointless as that first week!
There are two sorts of inspector -- HMI (Her Majesty's Inspectors) who are employees of Ofsted and Additional Inspectors (like me till yesterday) who are all self-employed and are offered individual inspectors on an individual basis by the contractors who run the whole thing for Ofsted. There are now three of these, for the north/midlands/south of England. HMI are not, incidentally, golden stars necessarily but ex-teachers who have chosen to take a different career path from their colleagues who apply to become Additional Inspectors.
I don't think from what colleagues have been telling me that we will have a case in law because of being self-employed and the terms of offering one-off deals being unilaterally changed. I do think that it was a horrible way to lose my major source of income.
Incidentally, it's not a fantastically high paid job. If you are a lead inspector (which I have never been, although I've been repeatedly asked to do the training) you get £400 a day. If you're a team like me you get £375, going down to £325 next term. This sounds great but last term I got four inspections which totalled five days in all -- and yes, this was STILL my major source of income! We don't get any expenses, we pay all our own travel and accommodation and food, and always have done (HMI get all this paid for, of course). We also pay for all our training. I did my last compulsory training days in December: with the cost of the course, the accommodation, the travel and food it came to £700. The next lot of training is in September and would have cost about the same, so I'm quids in on that anyway.