I haven't looked at the latest UN tender, but I didn't think they required a decent level of side blast protection, as you say they are B6 which is a ballistics rating and has little bearing on the load the door hinge or latch will have to withstand - it could be armoured with aramids or hppe and still withstand the ballistic threat (except ss109). If you look at current European armourers which who are building to a decent spec and you'll find that 9mm high hardness steel door armour has necessitated properly engineered door hinges and considerable reinforcement to the door cheek around the latch to prevent stress cracking from the extra load.
Do you find the crews actually use those additional shoot bolts on the doors? By the time you've fiddled with that ridiculous r-clip you've got to wherever you were going anyway