What’s the best thing to do with them?

The one for my gloworm x2 has given up the ghost, I’m guessing it’s a control board failure but don’t know.

It seems to charge and hold charge ok, discharges in about 2 seconds though but worked fine until it didn’t, no progressively shorter life or anything. (Same on two head units, different battery works fine)

Is there anywhere that repairs these things or is it most sensible to take it to the local recycling point?

Might be repairable, but TBH it’s probably cheaper to put it in the recycling.

If you want rebuildable have a look for the old style solarstorm battery cases, then pick up some panasonic or samsung cells and a charger that charges them separately which get’s round the issue of the cells going out of balance over time which is what usually kills runtime.

It might be worth emailing Mark at mtbbatteries.co.uk. He fixed my gloworm head unit and does batteries (as you might guess from the URL). He may be able to say if it is worth fixing. But my guess would be by the time you paid postage and parts/labour it would be about as cheap to buy a new battery from him.

Ta, will try Mark and see what comes back

Another solarstorm/pannovo battery case user here with Panasonic batteries.

Charges off a regular solarstorm/magicshine charger, or you can charge each cell in a smart charger.