Morning.
My feeling is that the 2199 (report form) just hasn't been changed from when it was in use during the Brexit transition period and that you would need both a UK TRE and a UK registered sim (the 1158 which has the LST content hasn't changed for ages). I may be wrong about all of this but ultimately I think you are going to have to ask the CAA. Do you have a UK TRE lined up? If so then maybe they could contact CAA directly on
[email protected] to get an answer to this, inc which non UK sim you plan to use? As they deal with a relatively small group, they are quite quick to respond to queries. If you are hoping to use a non UK TRE they could try the same and see where it goes.
I think the other UK registered sim is at Airbus Toulouse? Perhaps contact them to see if it's possible to get a slot and if required a TRE there - if so then it's logistics and money to solve the problem, if not then it might help your case to use a different sim if there is no availability.
Hope this makes sense, hope it helps.
Good luck.