This site has the best reference I could find and quotes Mr Shute...
http://www3.sympatico.ca/drrennie/memoirs.html
Quote:
The following definitions are quoted from the entry in a Supplement to the Oxford English Dictionary: (The Compact Edition of the Oxford English Dictionary; Volume III: A Supplement to the Oxford English Dictionary; Oxford, at the Clarendon Press, 1987.)
"Boffin: [Etym. unknown. Numerous conjectures have been made about the origin of the word but all lack foundation]."
"A person engaged in backroom scientific or technical research. Hence boffin(e)ry, boffins collectively; also the activity of a boffin."
"The term seems to have been first applied by members of the Royal Air Force to scientists working on radar."
1945 Times 15 Sept. 5/4: A band of scientific men who performed their wartime wonders at Malvern and apparently called themselves the "boffins".
** 1948 N. Shute, NoHighway III. 61 "What's a boffin?". "The man from Farnborough. Everybody calls them boffins. Didn't you know?"......"Why are they called that?" "....Because they behave like boffins , I suppose". ***
1948, Lord Tedder in A.P. Rowe One Story of Radar p. vii, "I was fortunate in having considerable dealings in 1938-40 with the 'Boffins' (as the Royal Air Force dubbed the scientists affectionately)".
1952 Picture Post 30th Aug. 20/I. Only a backroom boffin out of touch with the classroom could hold this pious belief.
1954 Economist 19th June suppl 6/3. The graduate from research - roughly....the boffin of industry.
1957 R. Watson-Watt Three Steps to Victory xxxiii 20I The proud title of boffin was first conferred on radar scientists by Royal Air force Officers with whom they worked in close cooperation...... I am not quite sure about the true origins of this name of Boffin. It certainly has something to do with an obsolete type of aircraft called the Baffin, something to do with that odd bird the Puffin; I am sure it has nothing at all to do with that first literary Back Room Boy, the claustrophiliac Colonel Boffin.
1958 Times LitSup 14 Feb 83/3 In one of those diverting interludes.....he writes an anatomy of Boffinry.
1958 Economist 25 Oct 298/I "The unexpected success of the boffins' conference at Geneva.... ending in agreement on the feasibility of controlling a nuclear test suspension."
1960 J. Maclaren Ross Until Day viii, 132, "I was engaged in some Boffinry in a blasted back-room unit"
http://www.worldwidewords.org/topicalwords/tw-bof1.htm
also mentions the radar story and that...
"a Nicodemus Boffin is a major character, a “very odd-looking old fellow”, in Charles Dickens’ Our Mutual Friend."