Yet another guesstimate required sorry

sparklewing

At the moment in our 3 bed mid terrace we have a baxi back boiler behind the gas fire in the living room a water tank in the bathroom and radiators in each of the downstairs rooms.

We want to get the back boiler disconnected(I presume we can just leave it in situ disconnected) gas fire disconnected(going to get an electric one installed instead), combi boiler put in the kitchen(about 3m from where the current boiler is), the water tank removed and 3 radiators installed upstairs, the downstairs ones are fine.

I have budgetted £2500 for this but now I'm worrying it's going to cost way more than this, waiting for some companies to come round and quote but has anyone has similar done or have any idea of potential costs.

Thanks