Am all to aware of the UK airspace, mcdhu, as I started to fly into LHR (and Europe) on a regular basis in 1974.
I should think that a sin bin could be devised without too much difficulty, how about (for handoffs from Europe)...holding over DVR at, say FL100, max speed 180 knots, one minute pattern (for high fuel flow) with a "don't call us, we'll call you" policy.
Shouldn't take too long for them to get the message.