and by all manufacturers.the term 'power shower' is generally used buy the general public
I don't think we will have to wait too long before there is an EU Directive and UK legislation limiting the flow rate from a shower.who has the right to tell client how much water he/she should be using , hot water consumption should be based on customers needs & not what you 'think'.
There is already a Building Regulation stating that the potential water consumption in new houses must not exceed 125 litres/person. A 30 minute shower at 10 litres/min ... work it out for yourself.