So:
you have a boiler which adequately heats the house at this time of year which is also the coldest time of year.
You have a cupboard which gets hot because the flue pipe passes through it.
You want to remove an already very efficient and clean burning boiler, and replace it with what will be little different in performance, but will cost a lot more.
You will have to install a condensate drain.
Installers just LOVE people like you.
you have a boiler which adequately heats the house at this time of year which is also the coldest time of year.
You have a cupboard which gets hot because the flue pipe passes through it.
You want to remove an already very efficient and clean burning boiler, and replace it with what will be little different in performance, but will cost a lot more.
You will have to install a condensate drain.
Installers just LOVE people like you.