It had been a long time coming, but I finally weighed in the batteries we used off grid, plus a bunch of others that had accumulated. The 8 off grid batteries weighed around 300kg, and I weighed in a total of 475kg. Add 5kg of brass (old taps and mixers) and I got a cheque for 278€, 15€ of which was the brass.
A bit more space in the garage!