I really dont see the need for permission, If they are in Thai waters.
"I really dont see the need for permission, If they are in Thai waters."
Translation: the Thai government (or businesses) don't want to PAY for the retrieval of these mini-subs. Better to stick the "country of origin" with the bill. These are British wrecks, probably not worth much as salvage, sitting in Thai territorial waters. The Brits have, in effect, "littered" in Thailand. It's only right to ask them to clean the mess up,and pay for it, too.
They may also still have "live" ordinance aboard, which while submerged in salt water for sixty years, might still go "boom" when you least expect it.