The BBC already have all the consumption data that they would expect - IP address, device, time listened, etc - in their own server logs. Just like a normal podcast player.
So... what user analytics do the BBC actually want?
There's a standard NPR have written to improve this, but it requires the podcast players to implement it. It's very privacy-respecting but I doubt Apple will implement it, so it's probably going to be a non-starter unless the big podcasters like the BBC hold the line.
For Google Podcasts, "downloaded" = "listened", since it has no auto-download feature. So they are (excepting the minority who manually download) actual listens.
You remind me that I should add a sniffer for RAD support in my Podnews pages, so I'll go and do that. My own podcast has RAD tags in it.
All other services (Spotify, SoundCloud, Apple, etc.) serve podcasts on their own properties but if Google does it it's monopolistic. To me such claims about Google have become too overused and have lost their meaning.
I don't blame BBC though for sticking to their guns because they really want user analytics and think have the weight to pull out. The justification they provided is just misleading.