Surprised to see a post like this from a esteemed professional! As I've posted on here before, we install electrics to fail, not just to work. Anyone, slightly above the level of idiot, can make electrics 'work' - it's what happens when things start to fail that's the difficult bit. To ensure that it disconnects itself in such a way as to present as little danger as possible to life or property.so after sleeving or taping the twisted earths, put the single cable in 1 light terminal, and the loop with the bit of insulation missing in the other. then if the new fitting is classI (metal with an earth terminal, connect the twisted earths to that).
1. it works..... hooray
2. it doesn't work........ aaaah shyte
3. it goes bang........ call in a sparks.
The twisted earth is very likely to be more than one wire twisted together, so the integrity of the connection is important to maintain earthing to other parts of the circuit. Twisted wires are not sufficient.
1. "It works". Maybe it does, but what's going on behind the panel? More DIY twisted together wires, that may have been loosened by pulling the wires while attaching the new light?
2. Lucky! The fault happened right away, before it could start carbonising, destroying insulation, and potentially cause a fire.
3. The safest outcome.