Oh dear, i completely misunderstood the preamble and made very heavy work of this, which really was quite striaghtforward - must read things at face value!!
Like most crosswords it depends on the compiler. The ones set by
DOC(who is also the Spectator crossword editor) are consistently
the easiest to solve.
I think that the one you cite 2177 - The Kate Bush theme was
middle range.
If you are familiar with barred grid cryptics you will find the
Spectator puzzles enjoyable.
Ironie and kayakamina,
I've gone for the 'A' version, which is in Chambers 12th, although only the 'U' version is in Bradfords.
Anyway, I've learnt what an inflected headword is!