moving the hot water tank into the loft?

Is this possible ?

There should be enough room to keep the cold water tank above it.

Thanks
Rob

Yes, but without shower/bath booster pumps and a booster/circulator pump for water to your hot taps you will have poor pressure. Also 1000 mm above the top of the cylinder would be required.

As long as the cylinder is under the tank, then you will have the same pressure as you always had. the tank height in relation to the draw off point (tap) dictates pressure not where the cylinder is positioned.