I'm pretty sure one of my panels has had it. This morning I noticed I was getting 0 watts despite it being nice and sunny, and the batteries being down to about 90%. Did some fiddling, disconnected the oldest of our three panels (which came with the boat) and suddenly we started getting power again! I also noticed our max voltage was higher, much more in line with what I would be expecting to get from the two newer panels. I've not done much testing on it yet, but I'm presuming the panel's had it.
So next comes what to do with the (potentially) dead panel. Dumping it by CRT bins seems wrong, disposing of it at a tip seems wasteful, but doing a quick search on Google only found solar recycling services for much larger installations than just one smelly boater with a single 300W panel. So my question is; is anyone aware of any recycling places near the canal that would take the panel? Ideally on the T&M or GU as that's where we're likely to be for the next few months, but I don't mind if it's not for some time - it's not exactly taking up space used for anything else.