I think Saddam Hussein and the Taliban would dispute your suggestion that the British will now only talk. As would the West Side Boys Militia in Sierra Leone who were destroyed in one of the most successful hostage rescue missions ever undertaken in 2000. :-)
I don't see the current mentality being able to respond to this seizure with anything other than talk, or maybe a capitulation with a prisoner exchange.
Most likely, the Iranians will release them once they have what they want, whatever that may be. The fact that they did this in the first place speaks volumes of their 'respect' towards the U.K.