In message , IMM
writes

More old wives tales! Some combis have pre-hearted heat exchangers
and some
with small pre-heated hot water vessels to give pronto hot water at
taps.

And most combis are further from the bathroom than a cylinder would be.
hence the wait for hot water.

Then put the combi in a more suitable place, like the loft.

What, right next to the other one ?

--
geoff