The pressure at the sink seemed ok, not great, but not too bad either. The hot water pressure seemed lower but wasnt too bad. I may pop round again with a weir gauge to check flow rates at all taps.
If you every want to be a professional plumber then you will have to learn that you don't assess water pressure by "seems".
There is only one way and that's by measuring the pressure.
At some point you will have to know what dynamic flow rate is too.
The electrically heated showers need a supply pressure of at least 0.5 bar and ideally 1.0 bar. Anything less and they will just not work.
As you will guess I don't think that you should be offering services to the public until you have a lot more ( two year min? ) experience.
Those college courses are meant to be an adjunct to an apprenticeship where you gain your practical experience.
Tony