How long should a Boiler last.

My Father has a Worcester Heat Systems Boiler which has sprung a leak at just over 3 years old.
This has caused water damage to his property.
Worcester Bosch are claiming that as ii is outside the 2 year warranty period they have no responsibility to do anything.
Is this correct as I would have thought that a Boiler that leaks water at this age was not fit for purpose or of satisfactory quality.
Any ideas on who to contact or what to do would be gratefully recieved.
I shall be contacting Citzens Advice as a starting point as soon as I can get there.

Thanks Tony,
The Boiler was installed by a local Tradesman who Purchased it. I have been told that Worcester Bosch only deal through their dealer network so I presume he bought it from a dealer nt direct from Worcester Bosch.