There are no hard and fast rules about the number of observations that can be carried out. As far as PMgt goes there is a "usual" limit of 3 hours (not 3 observations). These observations could/ should be multipurpose as it were. But schools can observe as many times as they feel the need, otherwise. If you are a maintained school or an academy operating under STPCD then you need to look at your Directed Time of 1265 directed hours per 195 days to make sure all the extras you are having to do does not take you over. If you have concerns then you could always contact your unions at county or regional level for support. Oh, for those in NASUWT, they have been asked to work to rule from 1st December!