"As you would expect from Crabtree, this is a sturdy box, but if you notice, which I didn't ( or rather I did, but the importance didn't register), this box has four mounting points for the face plate screws.
This seriously restricts what the box can be used for. For example, a 30ma RCD (Code 40097) won't fit as it fouls the top and bottom mounting points.
These extra top and bottom mounts also reduce the size available for the cable k/o points. I didn't try, but I imagine it would be very difficult to feed a 10mm t&e through one!"