Suffolk's diplomatic activity went on. He was one of the commissioners appointed to treat with France on 25 September 1348, and with Flanders on 11 October. The negotiations were conducted at Calais. On 10 March 1349, and again on 15 May 1350, he had similar commissions. On 29 August 1350 he fought in the naval victory, the Battle of Winchelsea. In May 1351 and in June 1352 he was chief commissioner of array in Norfolk and Suffolk.