you are completely confusing water pressure and flow rate, standing pressure is what pressure is in your pipes when nothing is being drawn and means absolutely nothing to you or me if it was too low then your water supply company will sort it, Dynamic pressure is what water pressure you have when water is being drawn and again nothing really to concern you but will be checked by a professional, flow rate is what you are confusing with water pressure and if you have 30+ LPM unless you are planning on building a block of flats then the pressure shouldnt bother you, you can have an unvented cylinder or a large combi and you dont need any tanks in your loft
