Have a look on here: http://www.diynot.com/forums/viewfor...56b9bf4dd91cfb


They can help loads on deciding what to get. If your having a combi it now has to be a condensing type, you will have to get a room stat and trv's on all your radiators. Go for one with a flow around 20L per min otherwise it will take ages to fill a bath. Not many cobis can run two taps at once, you need a thermostatic shower so you wont get burned when someone turns on a tap while your in the shower. Find one with a tank built inside it, that way hot water is nearer instant. Dont expect the water to be really hot when running a bath, combis raise the temp to about 40 degrees while a tank system gets to 60 degrees.