But I don't think this one is, as it all makes far too much sense.
The UK Border Agency (or whatever it's called these days) has revoked their visas, and that will undoubtedly be based on a change of circumstances since they were issued. There is no way Thaksin could have suspected this before he left, or he would have stayed put and probably applied for asylum. The UK govt wil be breathing a huge sigh of relief that the Toxins have made it all so easy for them.
As for the email, I'm not surprised it's relatively informal. Andy G is probably emailing all airlines about similar things on a daily basis. And it isn't a legal requirement, just a courtesy ("don't carry these people, or you'll wind up getting charged for their return journey").
A diplomatic passport is issued by and at the discretion of the government. Any diplomatic status T had would have lapsed long since, so whatever the passport number, his status would be that of any other (very rich) Thai national.
... providing they dig deep.
