for our new flats, storage heater will be better as all the pipes are hidden. You notice the gas pipe sticking out on the wall on the left side of your common toilet door? That's for connecting to the storage heater. If you go for instant heater, they will have to re-run the pipes and you will see the pipe running from your instant heater to your shower tap. Like in our parent's house. Will look rather awful.. This is what i gathered from the few IDs i spoke to..