I have a loft main water tank. I want to lower its height (at the moment raised higher in the loft by 1 meter to give more pressure I think) so I can put it in the eaves ready for a future loft conversion. I like the idea of a header tank for water shortages and being able to flush the loo if cut off. Will the height change affect the flow to my gravity fed shower which will be in a room immediately below? Many thanks.