Christian McArdle wrote:

[Combi-boilers] will heat only so much water at a time, so bath
filling tends to be slow. They are a good choice for houses where
the bath is used infrequently, as they are cheaper, smaller and more
efficient than a storage based solution.

I know Christian knows this, but to help clarify:

They are a good choice for houses where the bath is used
infrequently, or where bath-taking is seen as a slow, relaxing
affair and the 10-15 minutes to fill one can be taken to prepare
oneself for having a bath (this seems to take Mrs Socks about 25-30
minutes, so 10-15 minutes of that time simultaniously having the
bath filling isn't a problem!).
--
Selah