Did anyone else find this unsatisfactory.
If I've completed it correctly, the unclued
answers fall mainly in the NW quadrant of the
grid and are totally unrelated (and are not
thematic). When you spot the 'theme' the
grid fill becomes unique (although the BRB
gives 2 possible completions for 5dn; an
acronym and one other) - doubt you'd know this
without a computer searchable version of
Chambers.