I agree this is Britain’s problem but they will only have one chance to get it right.
I believe they should send in the necessary personnel to retake their property and when that has been accomplished take action to send an unmistakable message to the arrogant bastards in Iran.
My suggestion would be for Britain to seek out the two largest or most important ships in the Iranian Navy and sink them. It should be done both without warning and without acknowledging responsibility.
Repeat this each time the Iranians pull a stunt like this.
How ironic. If the thing was flying a SWEDISH flag it never would have been seized.