Tamaris, I knew I wanted one that would take the size of a large dinner plate for warming food up.
The one I've got does this, and that's because it's a 20L microwave which is pretty big and you may not want one that big.
I have always wiped my microwave out after use and leave the door open a little bit TO MAKE SURE IT'S THOROUGHLY DRY BEFORE i CLOSE THE DOOR.( Sorry, I just hit the caps lock by mistake, I'm not shouting) :-)
If you go to the Argos website (here's a link) and you can choose colour, price etc and this might help you choose.You can usually chat to them online or phone them if there is still something else you need to know. Hope you find the one you want.
https://www.argos.co.uk/search/microwave/category:33013899/opt/sort:price/