I think we are missing a point here years ago it was 7kw and that was your lot since then its 8, 8.5, 9,9.5, 10, 10.5, 11kw and we are all trying to squeeze 10mm cables into a 45A pull cord
so what next 15kw and 16mm ? the thing is electric showers in my view are absolutly useless plus people are shocked because they go abroad or to a hotel in this country that has a pumped system then comes home and thinks if I upgrade my shower then I will get that , well no you aint and when I get asked what electric shower do you have in your house I reply I will never put one in my house I have an immersion tank with a shower pump.