Cost of replacing strange boiler? I am getting my old 20 + year behind the times boiler...

I am getting my old 20 + year behind the times boiler replaced with a unusual up to date one and I am getting my water tank taken away and another radiator put in my lviingroom. Do you reason lb4000 is too expensive for all this mortal done? can I get a better contract?
Answers:    You won't buy a quality boiler for lb500, and you won't buy a clad installation for lb200, if you want a 5 years guarantee, a proper powerflush (manufacturer requirement, and takes at smallest 4 hours), a unit to prevent iron entering the boiler, and a perfect after sales service, you will settle around lb2600 for the conversion, the radiator maybe lb160. Many cheap one man band tend to go out of business within 2 years, or move house and can't be found, use an manufacture approved installer.
We have our boiler replaced this time last year and it be less than that
We have our old final boiler from the seventies removed and the hot water container taken out, an 2 radiators fitted in rooms where on earth there be none and thermostatic valves fitted to adjectives our existing radiators and it came to rather under lb2500. - British Gas quoted us lb4700 for like peas in a pod work!!