I never spoke to Ulster, tried to hand over a southbound Vulcan at FL410 to Midland one day... that didn't go away quietly.
I handed over a Lightning to Midland on recovery to Binbrook on one occasion.
Me: " Binbrook recovery, fuel priority, 040, edge of the dive, squawking xxxx, VFR"
Midland: "fine, throw him across, stud 5".
Neglected to tell him he was at FL680 descending....
Last few weeks before Binbrook closed and everyone was seeing how high they could get. The opportunity was too good to miss. They weren't happy when he checked in though.
Happy days.