Picaroon is one of my favourite setters. A couple of very minor niggles though. According to Chambers, the abbreviation used in 5a is only singular (unlike the preceding definition in Chambers which it indicates can be singular or plural). Also, in 6d, the noun in the clue is plural whereas that part of the grid entry is singular. Thinking about it, I suppose the singular could describe them in general rather than having to agree with the noun. I must have OD'd on the pedantry pills this morning!