We are just going to have to wait and see, my hubby really doesn't want a combi but I think when they came out some 18 - 20 years ago they were a bit iffy with the hot water pressure, I had one in my old house and while yes you have hot water all the time and you are only heating what you need just think prior experience has put, well both of us off tbf, they may have come on loads now technology wise and they way they work.
If we got rid of the water tank, that's in a cupboard in the bathroom we could then install a shower cubical there instead, ok ok I best stop getting to far ahead of myself, who knows, could just be a simple fix on our old lady yet