Further to the last entry, Ede & Ravenscroft, who supply court dress, have an FAQ:
bq. Q: What is the difference between the judges bench wig and the judges full-bottomed wig?
A: Judges wear the bench wig when they are sitting in court. It is a short wig that is frizzed all over and has two tails at the back. The full-bottomed wig is only worn on ceremonial occasions with full ceremonial dress. It is not worn in court by judges when they are hearing a case.
(What is a red bag? was news to me)
Wonderful illustrations in this 78-page PDF booklet called Legal Habits.
I learnt from the FAQ that the pouch at the back of a barrister’s gown is not, after all, for fees, but used to hold a hood.
Here’s a shallower link, with more photos.
And here’s a German equivalent.