Any question answered...

Double yellow lines:
http://www.direct.gov.uk/en/TravelAndTransport/Highwaycode/DG_069860 says "Double yellow lines indicate a prohibition of waiting at any time even if there are no upright signs."

Wikipedia http://en.wikipedia.org/wiki/Double-yellow_line#Loading_restrictions says
"Loading is allowed on double-yellow lines unless there are also yellow marks on the kerb or at the edge of the carriageway"

If there's no waiting at any time on double yellows, how can you load/unload as per wikipedia?

Liars!

Usually there is a time, when there is no loading.