It wouldn't be hard to come up with a verbal formula which could be interpreted by the British Government as denying any frontier violations while being interpreted by the Iranian Government as accepting that they had happened. The key would be to build the formula round a determination to avoid any such incidents in the future.

But of course that would be dependent on both sides actually wanting to avoid using this as as a stepping stone to heightened conflict.

That isn't unrealistic. The thing people tend to ignore is that Iran is only a few years out of a disastrous war forced on it by Iraq, which was comparable in terms of carnage to the Great War, in which Britain and the USA were in effect sided with Saddam Hussein's aggression.

Insofar as Iran is at least toying with the idea of developing nuclear weapons this is far better seen as arising from a desperate determination to avoid anything similar to that happening again, rather than as from expansionist ambitions.