Was that the day that the paper had Rufus's first puzzle? I didn't try the online one then, but I recall that it has lots of interrelating clues, as does this one.
It was the day that Rufus announced his retirement, so the paper reprinted his first published puzzle (which was much harder than more recent ones!) In typical Grauniad fashion, they didn't alter the online one - until very much later in the day, I think?
Yes, tanglewood. It appeared briefly online (we think) on December 18th, before being replaced by the Rufus one that had been printed in the paper as a tribute, and is now on the link I gave.
This is all very interesting, but hasn't helped me work out 5ac or 24d, which would be helpful to other clues.
Spiral starts tonight, so I haven't got much time and a meal to cook. We're still on leftovers!