Cryptic crossword No 1,407

Phew, what a head scratcher! This was really good fun but fiendishly clever and (as I’m not a particularly strong solver) I needed some assistance. I loved 27a - what a great example of what can be done with that device - 25a (very precise and funny) and my other favourites were 6a 7a 5d 9d and 13d. Spoilers follow…

Hello lovely people coming to solve my puzzle. Please do leave any thoughts and likes here, so that I can learn and improve. Further spoilery comments follow:

Pretty good stuff Catnip. Some really innovative thinking that perhaps very occasionally got the better of itself. But as a self-confessed learner (aren't we all?), it's a great base to build on. May faves were: 6a terrific start, 11a v clever 12a, 21a, 5d, 9d COTD, 16d, 22d. I'll look foward to your next. SPOILERS

I completed the RHS but struggled to make much headway in the West, Catnip. Somewhat beyond my solving grade and I needed quite a few reveals. Wavelength thing, I suspect. Of those I completed, 8d was my favourite with 9d and 2d making up the podium. Thanks. PM