It would be criminally negligent if UK was not trying to quietly engage with Iran diplomatically to it's best interests.
To jaw jaw is better than to war war.
As someone who is not in hock to the coven that is US politics I would happily agree with Iran not to attack or not to assist an attack in exchange for securing some nice Euro priced oil.
Hopefully goodish relations with Pakistan will stand us in good stead.
Of course Iran might demand an explicit renunciation of the UK-US alliance ....
If all of this can be done in concert with other (EU ?) nations, so much the better.