"pauliepie" wrote
| Is it right that the higher the cold water storage tank
| is above a standard vented cylinder the better pressure
| is available out of the hot water taps???

No. It is the height of the tank above the *tap* that matters.

| Is there a minimum height the tank has to be above the cylinder?

No; some combination tanks have the cold tank immediately above the hot, in
the same assembly.

Owain