Mojtaba Khamenei is not a foe of the UK and his country is unlikely to become an active adversary of ours. It’s more of a case of Iran seeking to assert itself in the normal ways than any special escalation of tensions.
This sometimes can be hard, and it takes up resources because large country’s need plenty of room in both a literal and figurative sense. But it’s not an indication of a large problem that would cripple us if we didn’t sufficiently respond to it in kind.
In response to an issue with a region making trouble before, Khamenei is reported to have said, “It can’t do anything wrong and so we leave it to go wild.” It’s been interpreted to mean he sees potential and proximity as threats, not simply the existence of others and life’s consequences.