I got the Rocket up to pressure.
Extracted one double shot
Turned on the steam for the milk - I got extremely wet steam.
Extracted 500ml from the hot water tap before the auto fill started
Waited until the boiler pressure was right
Turned on steam and had really dry invisible steam.
I did another extraction and steam - no problems.
Extracted 100 ml of hot water before auto fill started - which is about right.
I did another double extraction - no problems as above.
My findings are that the very first extraction seems to fill the boiler!
In the past my second follow on extraction added more water to the boiler and the boiler opv opened and release water.
In the past my third follow on extraction made a bigger puddle
The pressure in the boiler now was not steam but water a little compressed steam/air. So when the steam tap was opened I go water or watery steam.
"They never believed me"
I have no idea what may be causing this.
My work around from cold is the turn on, wait for pressure to build up. Extract 500ml of overfilled boiler water. Let the boiler pressure build up. Then test if the steam is dry. Then all will be well.