I need some urgent advice please!

I live in a flat and am about to have a new indirect hot water tank
installed. The guy who is doing it has also fitted new taps for me
throughout the flat, but the pressure of the hot water is awful. The
single tap on the bath is fine but the mixers in the bathroom, kitchen
and bedrooms have just a dribble of water.

I was then advised to have a megaflow fitted which would increase the
flow. I am waiting for a price for this but have also heard that some
taps are only suitable for high pressure systems, which may be the
cause of my worries, and just fitting new taps could solve it, and
save me a load of money! Also, what can I expect the megaflow unit to
cost?

Any advice asap would be most appreciated!