Bagso
I don't know about the RAF tanker incident which you mention but is was not unusual to "launch for diversion" during my time in the RAF. In other words you get airborne to get the job done and on return to base/completion of the task or a some later stage of the flight, you see what the weather is like at your intended landing airfield. If it's too poor, you divert. You would always carry fuel such that when you arrived at the "first" diversion airfield, you had enough to divert again. This was probably more common on the tanker as many other sorties depended on it getting airborne.