I suspect it would be difficult to restrain a person's right to employment unless there was something as unlikely as evidence of an intention to misrepresent inspection outcomes. However, both your governing body and the inspector involved are ill-advised to be contemplating the arrangement at all. Inspectors are bound by a stringent code of conduct. Specific guidance states unequivocally that inspectors must not exploit their position to secure employment for themselves or others where this would compromise their impartiality and thereby impair the integrity of an inspection. Neither must they suggest or imply that any gratuitous advice given by them after an inspection is a prelude to seeking paid work arising from the inspection.
Therefore both the governing body and the inspector in this case are likely to be seen as compromised; the former because they may be regarded as seeking a soft option, the latter because acceptance of payment for a separate but concurrent inspection in the same school implies the possibility of a partial judgment.
I would advise both sides to cancel their arrangement.
Bill Laar is a registered inspector. Write to him at The TES, Admiral House, 66-68 East Smithfield, London E1 9XY. Fax: 0171 782 3200. E-mail: firstname.lastname@example.org