Thanks everyone for your replies and comments, I always enjoy reading the views of others and seeing how they compare with my own. I would have replied sooner but for some reason I've had trouble logging on to the Forum today.
@Simon - You're absolutely right about 'Pine'. Chambers has it as No. 2 under the 2nd definition as a transitive verb "To consume, cause to wear away".
@Elle and Jazzgirl - Thanks for clarification of the plural of 27a (I did say my Latin wasn't up to much). The annoying thing is that, when I checked Chambers last night, it was only 'Sanctum' I looked under, hoping to see it given as a plural - which it didn't. However, today I checked again and found that 'Sancta' itself actually has it's own entry.
@Nodrog, Mattrom, and Matador. Thanks very much for your explanations of 24a, it makes complete sense now, much appreciated.
From reading the comments, I get the impression that the general consensus seems to be that, yes, it was quite difficult, maybe more so than usual, but good fun all the same:-)