Martin wrote:
Hi All,

I've been "persuaded" that the bathroom needs doing this year. One
thing I'd like to improve upon is the shower.

Currently it is a cold mains fed electric shower (Kw unknown) and it's
not good.

How can I improve it? I have no water tanks in the property at all and
snip
Are there any alternatives? Would it be worth running the new shower
straight from my new-ish Biasi combi?

Usually, yes.
Another alternative may be to add a heat recovery device in the drain,
which warms the incoming cold water.
This will dramatically lower the amount of water needed to be heated.

You need to say how big the output of your combi is (in KW), and the
size of the shower.
Turning the shower on hot, and observing the electricity meter should
tell you the size of the shower.

Is it likely the old electric shower's flow is being restricted by
limescale as we're in a hard water area?

Possible, but unlikely.
Most electric showers in this country are significantly limited by the
electrical power input.
It takes 4100J/l to heat 1l of water by 1C.

Or at .2l/s, and 40C temperature raise, about 24KW, or 100A at 240V.

Most showers are nowhere near this powerfull.