Finding this week's puzzle very tough, so reassuring to come here and find others are in the same boat!
I have (I think) solved 12 clues from Set B and 3 from Set B but nothing entered in the grid yet.
I'm pretty new to the Listener - this is only my 5th or 6th attempt - so parsing the preamble is still a workout for my brain. Though I've managed to complete all except Twisted Sister, even the numerical puzzle which at first glimpse might as well have been in Elvish or Klingon.
In this case - the fact that the clues are given in normal order presumably means that within each set all the Across clues are listed in ascending order first and then the Downs?
As for the symmetrical positioning - isn't this obvious from the symmetrical grid? I feel very dim asking this, but other posters have asked about / commented on the symmetry, and I'm lost as to how "their entries are positioned symmetrically" is useful information beyond the evidence of my eyes...
Apologies if these are silly questions, or asking for too much help. I accept that I almost certainly won't be able to finish this one, but would just like to feel like I've given it my best shot! Any help much appreciated.