In my 26 RR there's no space above the microwave; there is some above the fridge.
However I think there's more bang for the buck in looking at the space above the wheel arch, under the seats, and even a set of shelves above the seat on the LH side (matching the one on the RH side).
My photo shows I used the space above the fridge as a display area.
Sent from my iPhone somewhere on the face of the earth using Tapatalk