OK....Found the fill pipe (Braided Hose leading from undersink water mains)...It was very slightly open and a very small jet of water was constantly coming out when I disconnected the Braided Hose. Now i've turned it of (just a very slight movement on the tap) and the supply is now totally closed.
What now.........???? Lol
According to user manual.... Gauge should be reading 0.8 bar