My guess is that it was setup for the guy catching them at the other end. ML arrivals sector (YWE 125.7) would have been busy identing them, clearing them, starring them and sequencing all at the same time.
In fact from the guys working that sector, some a/c were calling them up for onwards as soon as they entered TIBA whilst others had to be chased before entering CTA at the other end without a clearance. All good fun.
The last guy who shut the airspace down (and was told by a pilot to go and enjoy an nice cup of tea, lol) had done 10 hours and basically coordinated all the traffic around his sector as far as he could see to get them at different levels before entering TIBA to make sure they weren't gonna hit. Apparently there would have been some very close calls if they'd all gone in at their planned levels (and not spoken to each other).