Could be............ but the overseas kit usually had a UK counterpart as they would be from the same production line. As mentioned it looks like one of the "Competition" family. I thought the GS with an erroneous 531c sticker done at the time of re-finishing.
No sign of any braze ons. Just marking to the paintwork in that area. I will post a few more pictures this afternoon that may help to identify it. Cheers for all your help so far.