[HAHalliday]

The OBE was gazetted 1 January 1946 so the citation will most likely be found at Kew in AIR 2 documents dealing with the New Year 1946 Honours List. Search their catalogue, limiting the document field to AIR 2, the time field to 1945 to 1947 and using key words "Honours" and "New" and "Year" or "Years".