Any question answered...

Ta but I still don't get it.

"Double yellow lines indicate a prohibition of waiting at any time even if there are no upright signs."

Does waiting include loading/unloading? Can I unload my car on double yellows or not?

Southwark Council, FWIW, sez, "it depends"

http://www.southwark.gov.uk/info/473/guide_to_parking/499/loading_and_unloading/1

You can stop to load or unload on both single and double yellow lines if

. your vehicle doesn't cause an obstruction
. there is no loading ban in place

If a loading ban is in place, it will be shown on the parking signs on lamp posts and by yellow stripes, also known as blips, on the kerb.

One stripe means that you can only load at certain times, check the sign for times. Two stripes mean no loading at any time.