So let me get this right. NATS didn't want the flights to land because someone couldn't bring themselves to do the authorisation (I doubt the ash conditions improved), but were quite content to have them circling in a holding pattern in the "ash contamination" area.
Yep, many of the posts have been cleaned off but it appeared the BA aircraft were put into holding at places like LND, then a couple were given direct to EGLL and EGKK with the speed up, then put into holding again, at lower altitude. I have online access to near realtime ADS-B data.
If 2100Z was a hard constraint, it seemed to be waived for the Vancouver bird, I watched it land several minutes before the hour. Someone suggested it was timed for the news at ten, perhaps not that farfetched considering the media circus and brinksmanship going on.