No doubt about the reverse feed, turn on the cold and you get low flow, turn on hot and flow reduces yet you hear more water flowing and a few minutes later water starts coming out of tank overflow. Off to buy a new tap...
At least I know that tank overflow isn't blocked ;(
I think there are two problems, a very big mismatch in pressure between hot & cold and a very small feed into the tap as cold isn't that great either compared to old tap. I think we need a simpler design for a low pressure hot water system, pity tap actually looks really nice.
Had to replace our old simple mixer tap because it started to leak so bought a shiny new mixer with pull-out hose. All the other hot taps in the house upstairs and down are ok but only a dribble from new mixer in kitchen. If the cold is turned on then tank in loft overflows so I suspect that hot...