Scramble launch with a single interceptor for a single target sounds very reasonable. And, by the way, American controllers were serving alongside the Brit controllers back then (even today we have exchange officers). If the situation appeared threatening at time of launch then I am sure more jets would have been launched at this stationary target.
Wow, a sensible, knowledgeable explanation.
Of course, hell will freeze over before a naysayer will admit such a sensible explanation as remotely possible.
But that’s another issue.