My father (and his Company) was posted to 3rd Bn. No 1 I.B.D. at Fort de L'Eau near Algiers on 27th March 1943. By 5th April his address was No. 3 C.R.U. He remained with this group until 20th April when he rejoined 1/6 East Surreys. What were No 1 I.B.D. and No. 3 C.R.U. The I.B.D. War Diaries (National Archives) do not mention 3nd Bn. I.B.D., and I can find no record of a No. 3 C.R.U. Could C.R.U. stand for Corps Reinforcement Unit? If so, who did they report to, and where might I find their records?