The young faces of the Laffin crew out on the airfield, training either in a Heavy Conversion Unit (H.C.U. - January-February) or Operational Training Unit (O.T.U. February-March).
See the crew photo dated 13 April 1944 (Night Raid on Happy Valley or Crew photo's) they appear to have weathered 2-3 years in a span of 3 months.