Looking through my late father's papers I found BELSEN CONCENTRATION CAMP PASS 'B' Serial No 30/2 No ...... Rank S/SGT Name ....... Regt/Corps RAMC is stationed in the Camp Area and is authorised to enter Camps 1/2/3@ and Hospital Block on duty. Date of issue 2/MAY/45 .......... Colonel, Commander. No 2 Control Section. Signature of Holder ............... NB. No person will enter any of the above unless fully protected by Typhus Innoculation and dusted with AL powder prior to entry. @. Delete where applicable. (nothing deleted) It's stamped "No. 30 Field Hygiene Section RAMC" "Orderly room File Index No. ....." So he perhaps wasn't there when it was liberated but quite soon after.