On Friday, 4 November 2016 14:30:53 UTC, ss wrote:
I will be wiring in 2 x LED ceiling lights,is 1.5 mm twin & earth the
correct size, or should it be 2.5 mm?

1mm as you now know. I wonder if one day bell wire will be accepted again for lighting. Today's high efficiency lights don't need anything heavier. If it's kept out of touch it doesn't need double insulation. Earthing may fade into lesser importance with RCDs & class 2 fittings.


NT