Thanks for reaching out.
I've tried checking BBC regarding this and here's what it says:
Listeners will have difficulty accessing BBC podcasts via the Google Podcast app and they will not be able to directly access BBC podcasts via the Google Assistant (Google Home).
In the UK, listeners will still be able to access our podcasts on the free BBC Sounds app and website. UK listeners using Google Home can continue to access BBC podcasts by casting from the BBC Sounds app or, if using a laptop, the BBC Sounds website on the Chrome browser. Outside the UK, listeners can access our podcasts on the BBC Sounds website (where casting is supported) and the BBC Sounds app (where available).
Hope this helps.