UK Differences
Note that the holding speeds in the UK differ from ICAO standard. I can't find that bit of the AK AIP on line at the moment so I can't post the accurate data for all Cats. But it should be in the Jepps.
From memory, for Cat A and B, they are
Up to 14k 230kts
14k to 20k 240kts
20k to 34k 265kts
Unless the hold is part of a procedure where the speed is promulgated as being higher.
I know it is a bit sad remembering these but we had the ops inspector fly with us only yesterday and he asked me this exact question. I could not answer it which is why it is fresh in my memory now!
MM