I'm trying to understand what you mean by this. Their podcasts still show up in e.g. Apple Podcasts and Pocketcasts. If you look at the 'podcasts' page for e.g. '13 Minutes to the Moon'[1] (which I hadn't realized there was a third season of), there is a (small) link to the rss[2]

[1]: https://www.bbc.co.uk/programmes/w13xttx2/episodes/downloads [2]: https://podcasts.files.bbci.co.uk/w13xttx2.rss