Rap, a "knicker flash" is used on the Usenet newsgroup ukmediaradioarchers (UMRA) to denote a boast about own, or offspring's achievements.
Knicker is, of course, used in it's UK meaning of an item of ladies' underwear!
Royces is Roll Royce, the aeroengine builders, and Welbeck is the MOD funded 6th Form College for future Engineering officers of HM Forces. He pulled out because he's more interested in doing rather than supervising.
Apparently he got top score on the interviews!!