Would like a better electric shower

[flameport]

Fit flow restrictors in the outlets, partially close the service valves in the pipework (this will probably create unwanted noise), fit pressure reducing valve(s) as required.
However it's all a waste of time - your electric shower has no means of temperature control in it. The only thing which determines the temperature is the flow rate through it, more flow = cooler water out, less flow = hotter water out. Most electric showers are the same - when you 'turn up the temperature' all you are doing is reducing the flow of water through the heating chamber.

One of the few which has semi-reasonable temperature control is the Mira Advance ATL, but that costs c. £300. It's still feeble compared to any other type of shower, and a thermostatic mixer can be had for substantially less.

 

[stealthwolf]

One of the few which has semi-reasonable temperature control is the Mira Advance ATL, but that costs c. £300. It's still feeble compared to any other type of shower, and a thermostatic mixer can be had for substantially less.

I did see that model and toyed with the idea of buying it. A mixer shower would mean more involved work and is something I'd wait until we redo the bathroom.

 

[Agile]

Your problem is caused by a reduced flow through the shower when other outlets are opened.

So a pressure reducing valve on the shower could well help to maintain the same pressure ( thus flow ) through the shower.

But reducing the flow taken from the taps would also help.

As probably would fitting a new mains supply pipe from the road.

Tony