Might give the exchange a whirl - thanks.

I did find a comment elsewhere about pushing the tray base in without the metal top - apparently it "clicks" into place then. Will try that first.

Thanks. It didn't appear to overflow for me - although maybe it would have if half the water hadn't been directly dumped on the counter lol.

Based on the pics in the manual, I had to hunt around to find a container that was a) big enough to hold 2 litres, b) small enough to balance on the drip tray and c) low enough to fit under the portafilter. Answer: no such container exists - I think it's physically impossible. Fortunately the images in the manual were ridiculous and, as you say, most of the water is squirted into the drip tray and barely anything comes out into the container sitting on top. Silly manual!

Thanks. I've noticed there does seem to be a tendency for the drip tray to wiggle slightly free. Like there's almost two locking positions for it - locked and really-locked - and it likes to sit in the less-locked position. I've been more careful about keeping it well pushed in over the last week and haven't even noticed drips underneath on the machine base, so maybe that's the issue.

Someone did point out that there appear to be unused spaces in the plastic molding under the drip tray for rubber feet. I might try adding something there which hopefully will make it less likely to walk itself out of position.

I'm going to given it another cleaning cycle in the next week and be sure that the tray is all the way in - that's the toughest test I think.

I don't believe, like I think was @avidamoeba@lemmy.ca's implication, that there's a leak inside the machine.