hi i have a ideal classic rs40 wall boiler and its started making loud banging noises! i have also had a heating element replaced in the central heating tank in the airing cupboard and was told that there was a lot of slug in there. They told me i should get the hole lot replaced as it could pack up at any time. great hay! the water tank is split cold on top and hot on the bottom can you tell me what the problem is or if/how it could be solved. also what sort of price would you expect to pay for all this to be replaced. kind regard steve.