best replacement for ideal concord wrs 255a

[mkultr4]

Hi

i Know next to nothing about central heating

My mums 30+ year old boiler has stopped working (IDEAL CONCORD WRS 255A).
The unit is covered by british gas home care
british gas have said that it needs a new case seal which they claim they cannot obtain due to the age of the boiler - so they have disconnected boiler.
They have offered a "solution" of replacing the boiler with a worcester greenstar 28i junior combi - the price of this supply and fit is over 2 thousand pounds - they say that as well as fitting the boiler, more work will be required to make system work with a combi.
British gas have advised that the current heating system installed is a gravity based system
We have no intention of buying a new boiler from british gas. We have also informed them that we have found the part available on the internet

Could anybody advise what the best replacement for a CONCORD WRS 255A would be, which would require the least additional work/cost?

The house is a medium/large detached - i have entered the dimensions, ceiling heights, loft insulation type etc in a online boiler size test and they seem to recommend an 18KW boiler - this sounds pretty small for a larger than average detached house - 1 radiator alone is about 6KW


any advice would be appreciated.

Thanks

 

[mkultr4]

British Gas have now mysteriously discovered that they can source the part and are fitting it. Good old British Gas.

I would still be interested in knowing the best replacement for this boiler with minimum outlay.

Thanks