By the end of April 1942, Barron had completed 39 missions, 29 as aircraft captain, and finished his first tour. Now a pilot officer, having been promoted earlier in the year, he was awarded the Distinguished Flying Medal (DFM) the following month, the citation noting that Barron was "most reliable, efficient and courageous, pressing home his attacks regardless of opposition." It was typical for aircrew that had completed a tour to be rested and perform instructing duties for a time. In Barron's case, he was posted to No. 1651 Conversion Unit, stationed at Waterbeach, as an instructor. After a period of leave, he arrived at Waterbeach on 21 May but within a week was called back to No. 15 Squadron to fly in the 1,000-bomber raid on Cologne. Prior to the raid, he carried out a minelaying mission to the Frisian Islands; he described the operation as being "to get his hand in again." After the Cologne mission, flown on the night of 30/31 May, Barron participated in the followup large scale bombing raid on Essen, two nights later. He then returned to Waterbeach to pick up his instructing duties, which he soon began to find dull, despite being involved in four more bombing missions involving significant numbers of aircraft.