http://www.caa.co.uk/docs/33/269PLS.pdf
There is a charge now for authorising none UK TRE's/exminors which I expect the other authorities will also be doing.
It has for years been cheaper for some nationalities to get there checks done in other states due to the expense of getting a local to do it.
Also as well it will stop folk going to second countrys for type ratings unless the TRTO/customer stumps up for the authorisation fee. Before you just need to send the sim cert and examinor paper work and they would issue the TR.
Maybe its to stop pilots migrating to one authority which costs the least. I know alot of swedish pilots converted to the UK purely because every time they did a check it didn't cost them anything were as at home it would have cost them 400-500 euro to just get it entered on thier license. ATPL upgrades were done with a company TRE and were a paper work exercise where as at home it was a seperate sim session with a state examinor and cost a fortune.