Advice on choosing a boiler please.....

Pincher

You do this kind of stuff when you do major renovations.
Otherwise you get a unplanned abomination that looks horrible.

If you must have a combi, my vote goes to Intergas.
The only proviso is you should get somebody trained on it, to install and maintain, otherwise you will find a monkey scratching his head wondering where's the diverter valve, so he can test it.

Check out the warranty on these BAXI 10 years, Vaillant 7 and Glowworm 5.

www.plumbnation.co.uk