Hmmm… According to 145 Squadron history

http://www.scribd.com/doc/23762263/History-of-RAF-Squadron-145

Early August, 1942, Idku, a rest period for the squadron, this was short lived, with continued actions, and on one period an attempt to intercept the high flying JU 86Ps, a Spitfire was stripped down, intercepted one at 40,000ft, but unfortunately the guns froze…