tbh it belongs to the property owner. If you remove it without permission your on shakey ground im guessing. Best put something in writing when you give them your quote/ t and c's.
i had a mate who was working in high rise for a main contractor. The first few flats he took the large combined cylinder and scrap pipe. He then got told he was stealing and it had to be handed over to the main contractor or he would be reported to the police. So the next one he removed the cylinder from the cupboard, placed it in the lounge and filled it back up with water. He never got asked for it again.
i had a mate who was working in high rise for a main contractor. The first few flats he took the large combined cylinder and scrap pipe. He then got told he was stealing and it had to be handed over to the main contractor or he would be reported to the police. So the next one he removed the cylinder from the cupboard, placed it in the lounge and filled it back up with water. He never got asked for it again.