Bath water flow problem in new bathroom

Gangu

We've got a refurb underway. We bought a Monsoon 2 bar brass body pump for the shower for about 400€ at the plumbers suggestion. However the water flow in the bath (which is just installed, no tiles or flooring down yet) is crap. We thought it was strange that the majority of bath/shower mixer fittings for the bath were medium or high pressure, but our plumber said we'd have to get a tap that was .2 bar or less for the bath. Anyway that is what we did. It is a good brand, Roper Rhodes. But the bath pressure is still crap. It takes 6+ minutes to fill less than half of a 170mm bath.

Do others agree that this is crap? Is it unreasonable to tell them to attach the pump to the bath? They are saying its very unusual (quote "I've never seen it done") and will cause them all sorts of hassle. I do not want to cause problems, but it doesnt add up for me.

Am I being unreasonable? If the majority of bath/shower mixer fittings are for medium or high pressure how do other plumbers achieve this pressure without a pump?