as we've never once hung any clothing, and in fact long ago shelved it anyway for folded stuff there was the option to set MW into it with access over the sink,
cut a template of oven front in cardboard and tried it out at various heights then marked out best option and set up a router to cut out aperture neatly


By a fluke Keith the Router (with a handle unscrewed one side) was small enough to travel along that guide into corner enough, and the same going upwards in that corner below locker, but couldn't use the tool holder would have been too cumbersome so its just 'resting' on guide edge
here you can see first slot cut and the shelf the oven will sit on inside cabinet

top slot cut

both sides together with guide for router to push against and keep vertical



Last cut and pop out the waste square ready to clean up



Enough for first day, tomorrow try the oven in place, mount it securely in cabinet, there's still access to the heating header tank in background, probably create a further ply shelf above oven
also need to add a small surround on face of cabinet for neatness