Andy
2nd Lt Norman Roberts scored two victories in F2b C6403 (on 12 March 1918), one in C805 (on 10 May), one in C983 (on 25 June) and one on C943 (27 June). Unfortunately I can't say which, if any, of these machines was the number 13 to which you refer.
He received the Distinguished Flying Cross, the announcement appearing in the London Gazette of 21 September 1918.
VBR Graeme