if it was to the ensuite they can move the door opening to fit one in. For the kids bathroom you could encourage the draftsmen to change the plans to include a csd, a bi-fold door or have the door open outwards. The only issue I would have opening the door outwards would be the linen press.
Looking at the drawings I can't see how it can be structural, there must be another reason. As you have not even signed off on the drawings heaps of changes can still be made.
So I would ask why you couldn't have one, the question it and annoy them until they put one in
Also the toilet room is 1.55m long, have you compared that to your current toilet? In ikea they have a wall fixed cabinet you can put in the toilet/bathroom to have more storage.
).
. So this one shouldn't have much problem, but I still loves to have some more space there 
. Its going to be there for quite some time, even I dont like it much.
. its really not enough for me, but cant help