If you've the space for an isolator switch in a cupboard, you've space for an outlet plate. Iso's exist for a reason, especially for domestic cookers. Whilst there's no specific regs that require you to have an OCPD > ISO > OUTLET arrangement, it's been done that way for decades for very sensible reasons. Namely, that if the darn thing catches fire you want to be able to turn it off straight away without having to spend five minutes ploughing through coats and vacuum cleaners to find the consumer unit under the stairs. Therefore, if you have an ISO, you also want a more convenient means of making a connection to it - hence a cooker outlet plate (which doesn't have to be fitted behind the space for the oven, it could be another cupboard away).