About Lighting when stopped: which statement is correct?
If your sidelights are enough to stand still, they're also enough to drive away with, as long as you take it easy.
As soon as you unhitch your trailer or caravan and leave it standing separately, the lighting duty when stopped no longer applies — it only applies to the coupled combination.
If you are stationary on the carriageway outside the built-up area at night, side lights are only advisable, not mandatory.
Inside a built-up area, sidelights when stopped somewhere dangerous or a nuisance are 'advisable, but not required.'.
Explanation
trap: advisable confused with required. Book p.186 - inside a built-up area, sidelights when stopped somewhere dangerous or a nuisance are 'advisable, but not required.' The hard requirement only applies outside the built-up area and on a lay-by/hard shoulder along an expressway or motorway