They still shouldnt have one
I suspect that royal navy submarine fired tomahawks could sink the majority of it in 24 hours or so.
I don't know if the RAF has the air assets near enough to conduct strikes on Iranian targets. Remember, they no longer have big strategic bombers, and the few carriers they do have right now only have Harriers on them.
Unless they are moving planes to forward Iraqi bases, its going to be hard to do bombing runs.
I suspect it will fall mostly on the royal navy to do missile strikes with assistance from the U.S. Navy.