re: So what do you think is the best strategy?
My strategy? They wouldn't have been allowed to take the sailors in the first place. This was a test, and Britain failed it.
At this point, Iran should be told to deliver the sailors, with a reasonable deadline, or their ports will be blockaded. No bombings, no attacks, just shut down their shipping. There is a move or two beyond that to ratchet up the pressure, but it would involve actual limited military action in Iraq. As far as I am aware, they have only one working refinery, and import most of their gasoline.