Hi, I have a flat which has a vented, direct combi hot water tank. There is 2 immersion heaters. One on economy 7 and another that acts as a boost at any time. It is a ground floor flat. I need to replace it as it is leaking and has been for some time. I am trying to decide whether to get a like for like replacement: https://www.tradingdepot.co.uk/rm-1200-x-450-copper-direct-economy-7-combination-hot-water-cylinder or whether to get a unvented unit such as: https://www.screwfix.com/p/rm-prostel-unvented-direct-cylinder-120-litre/51564 Thoughts please? It only serves a kitchen and bathroom sink. 2 people live in it.