I kept mine in my room, in a bag with only the bars poking out.
On the one had there’s not much they can legally do to stop you.
On the other landlords have the ability to make your life utter misery until you move out.
Just find one that’s Ok with it to start with, or has a shed/garage. It’s not worth the hastle of dealing with a douchebag landlord on top of the hastle of having to get the bikes spotless every time you take them out.
A house to yourself is a different matter, my road bike lived permanently on the turbo in the living room, the big bike in the under stairs cupboard, and only the muddy SS in the shed. This in spite of the a no bikes clause. having to keep it in a bedroom is a real PITA unless you really have no options.