<<ATC had a flight very close to the airfield but, on the face of it, didn't seem to have a full picture of what was happening. >>
Not sure what you mean by this as you have not provided sufficient information. In those days Hurn may not have had radar and would have depended almost entirely on pilot reports. If the aircraft was at 13000 ft was it in Controlled Airspace? If so, was it under the control of London Airways or London radar (from Sopley)?