I'll try and be accurate as to what has happened. Machine was turned on, and I waited until it had come up to pressure. This it did with no sign of any potential issue. There was plenty of water in the reservoir as I had just taken it out to clean out and refill. It had taken a little jiggling to place back in and had 'grabbed' a little before fitting into place. I moved the handle upwards to run some water through the head as I usually do, and there was a small amount of water followed by steam only.
A quick check of both steam and hot water wands gave me 'blustery' steam and boiling spluttering water from the two wands respectively. I turned the machine off and left it for half an hour before checking again, and got a similar result. It has sbeen left off since.
I won't be able to give Barazi a call until Tuesday, so any thoughts on the cause of this would be most appreciated if it is something minor (or otherwise).