The silver L-shape valve in the centre of the photo there is slowly leaking where the (narrow clear) input pipe comes into it. It starts to happen as it comes up to temperature, just a slow drip. This collects underneath and then eventually pools enough to mostly run out around the steam wand itself. I’d noticed that happening just this last week or so, but going by the deposits it’s been doing it a while! Sneaky.
I guess I need to track down and replace the L-shape part but if anyone has an alternative fix or guidance on how to actually swap it, I’d be grateful. Looks a tight place to try and work and I’ll be approaching it as a novice. Thanks!