He says combi and it may just be that. (snip) I would fit a
combi.

Wow. For the second time in two days, I'm in agreement! (Provided she is
aware of the significance of the limited flow rate).

Multipoints tend to be fairly low quality old inefficient designs. Many
don't even modulate, making the water temperature fluctuate even at low
flows. The combi will usually provide a better and more stable system and
probably with a higher flow rate, too. However, the installation will be
slightly more complex and might involve slightly more external pipework.
This is probably outweighed by the fact that you could install central
heating later for little additional cost (just a few radiators, TRVs, room
stat and some pipes). Even if she is anti-radiator herself, the fact that
real central heating could be added cheaply would add to the value of her
home if she decided to sell.

Christian.