Tall oven unit and built in oven,13amp plug and go.

Firstly it shouldn’t be plugged into the standard ring final circuit. If it has a plug then the relevant socket should be on a dedicated cooker circuit. If the socket is behind the oven it’s not ideal for a number of reasons, and would require accessible isolation in the event of a fault. BS 7671 clearly states appliances exceeding 2Kw should not be plugged into ring final circuits due to loading. Whilst it’s not statutory it’s good advice. It will work ok but if other high power devices are used at same time then you could encounter nuisance tripping. Also assuming your sockets are a ring.

You can plug it in the socket, it's ok to do so

I would agree mainly with the answer, mentioning BS7671 not plugging directly into ring main which could overload current load and trip circuit. If you are going to 'plug and play' your oven and the socket ends up behind the oven unit then at least put a Isolation/ grid switch near oven to enable isolation before attempting to remove oven for any reason

I would agree with the answer, an oven needs its own dedicated circuit and accessible isolation, not to be plugged in behind the appliance.