I have had two sets from DG. First one just failed after the long layup during the winter when I did the head, maybe I knocked it? DG sorted me out (top bloke) and I have the old one to try and fix one day. I would have offered it if I had known. I was always going to try drilling the rivets out and take a look. There is a dodgy connection and certain lights only work at odd times, but all lights will come one/work.
DG said these are being made part time by some old dude, so the supply will run out one day :-(
Sorry to hear about your back.