yet another shower query - pressure equlizing valve?

[watereed2003]

Hello all

I want to install a shower ideally using mains pressure cold and gravity fed hot as the supplies are close by... The way I see it my choice is:

1 Trevi boost/venturi type shower 2 Fit an extra cold feed to the shower from the header tank and use a mixer shower

but... could I just use a pressure equalizing valve with a mixer shower and remove the need to run an extra feed from cistern? the bathroom is in an extension and I have no easy route through roof void to get feed from cistern. seems this would save time and money as venturi/trevis cost =A3250 and up.=20

Any help much appreciated