Well it is a bit bizarre to put a switch/socket there, but it is not actually dangerous tohugh I doubt it meets the requirements for accesibility. I did find this older (2005) NICEIC guidance note:
The switch or control unit should be readily accessible. It should not be positioned behind or above a cooking appliance such that a person would have to reach over the appliance in order to access the switch/control unit.
The horizontal distance between a cooker switch/control unit and the appliance(s) it serves must be sufficiently short for the switch to be under the control of persons relying on it for safety. This requirement is likely to be met if the distance does not exceed 2m.
The height of a cooker switch or control unit in an installation in a new dwelling should be suitable to facilitate access by persons in wheelchairs and others whose reach is limited (as should the heights of all wall-mounted switches and socket-outlets). Based on the recommendations of Approved Document M, applicable for new dwellings in England and Wales, the height of the switch or control unit should not exceed 1.2 m above finished floor level.
Installation of a cooker switch or control unit in a cupboard or cabinet is not recommended. Potential users of the switch/control unit may not be aware that it is there, or items stored in the cupboard may obstruct access to the switch/control unit. In any event, wiring and other electrical equipment should generally not be fixed to a cupboard or cabinet, which may be removed in the future; they should be fixed to the building fabric.
It is also not recommended to locate a cooker switch or control unit in a central wall-mounted control panel together with others witching devices, as this may result in the switch not being under the control of persons relying on it for safety or otherwise not being suitably accessible. Where a cooker switch or control unit is positioned in such a central control panel, then, as for any other item of switchgear or control gear, a label or other suitable means of identification must be provided to indicate the purpose of a cooker switch/control unit, except where there is no possibility of confusion (Regulation 514-01-01 refers).