Didn't Iran see what happened to Argentina? Don't mess with the UK.
That was the UK of 25 years past. They will not respond other than with talk.
It becomes a diplomatic incident. No military action will be taken. The same as the U.S. Navy EP-3E being detained by the Chinese.
Ya think? I'm not sure, that was then and this is now. No Iron Lady in the UK now.
In fact, I think if Tony was in charge in '81 that Argentina might still be in the Falklands.