Excuse my lack of knowledge about this..... my cold water tank is in the loft, the hot water tank in a cupboard in the bedroom, next to the bathroom, and the boiler is in the kitchen. There is a pump by the hot water tank (I assume heating system). So how does my hot water get to the bath !!!!! 
The pump probably pumps both the hot water and central heating if you have a 3 way valve (when I say pumps the hot water, I don't mean to the taps.....it pumps the water from the hot water tank to the boiler)
It matters not where your hot water tank is....it could be on the ground floor....the pressure at the hot tap comes from where the cold water tank is.
Imagine syphoning liquid from a jar into another container.....the lower down the 2nd container is the faster the liquid flows....bring the 2nd container up higher and the flow slows. Bring the 2nd container up higher than the first and the flow stops.
HTH