Thanks to Jono for the grid and to Masquerade for a great puzzle. Finally finished this morning. I liked the theme. Last ones that held me up were 65 and 50 but both very clear from the wordplay eventually.
My answers to 12d and 15a fit in with every interlocking clue except each other, and I have no idea which is the clue for 46a. I'll go and look at the AZED for a bit of light relief ...
Thanks Jono, you are the star of the show toda. Ive never heard of that collective noun for finches, it fits them beautifully. Is the completed thematic answer a song or a singer?