Certainly Champagne - there wasn’t a proper (possible any) wine industry in the UK at the time. Champagne had long been the default sparkling wine for special occasions.
So it says but it almost surely refers to a dock trial, where the propulsion plant was run, propellers turning, with the ship firmly tied to a pier. Not necessarily at full RPM for high powered ships. Without the load of the propellers the turbines would overspeed with very little steam flow. It would be a useless and dangerous exercise to run them that way (if the shaft breaks or propeller comes loose in service you hope the turbines’ overspeed safety trips will actuate fast enough to prevent them destroying themselves but it’s not a sure thing).
In the Queen Elizabeth’s case, that would mean the propellers generating a current into the Clyde at an angle for several hours (ie it would push things towards the far bank or upstream). Ships would presumably have been sailing up and down the river during that time, passing within tens of yards of the propellers. Do you think it could have happened this way?
This is a plan of the area in question. The QE and QM were fitted out in the dock nearest the top of the frame; they were so long the sterns jutted some way out into the river.
(Incidentally the line of the launches is marked roughly by the dotted line next to the E of ‘Clyde’.)
It would not have been done without the propellers, or with the shaft couplings disconnected. Again that would be dangerous on a turbine ship besides not determining much.
The position of the ship or strength of moorings available may have limited the dock trial to relatively low RPM. That’s suggested in what you can see in Google Books ‘snippet view’ of a postwar article about it.
searching on
“queen elizabeth” “dock trial”
‘Dock Trial. … of course, carried out, but, as it is impossible to moor a ship of this size sufficientlv securely to enable the engines to be run at anything except " dead slow," the trial was not thought to be adequate.’
Dock trials are standard, this wasn’t just because they were in such a hurry to finish QE and it couldn’t run formal sea trials. You need to know the propulsion plant basically works before casting off and relying on it, or relying on tugs to prevent bad outcomes if the ship’s propulsion system doesn’t work.
With the exception of a few public areas in first class, the"Queen Mary" was never air-conditioned during her 30 years at sea. While most of her voyages were between the UK and New York - a fairly “temperate” zone climate-wise - much wartime travel was done to/from Australia as well as south-east Asia with thousands aboard - sometimes 12 to a room, and no a/c.
Even today, as a floating hotel, it’s not easy getting cool air to all the rooms (but the portholes still open).