Yep, I believe the upper role cages are the same. IIRC they were originally a smaller version of the roll cages that are on the Aussie SAS 6x6 Landrovers. The UK then liked the SROV design they ordered 200 for themselves.
I've got some Aussie SAS Landrover pics if you want to post them up, I've run out of space at my location so I'd need to send them to you for posting on here.
It will be in about 5 hrs once this post hits the forum as I'm not at my normal location
Nice designs on those Landies, the US also has some other Ranger vehicles I've seen which were cut downs and painted matte black,
I've got a bit of a soft spot for the old Landies, they climb like a billy goat..