"Broadcast" dates for Sounds-only podcasts

[Mike Crowe]

Does anyone know how to programmatically get the episode dates for
Sounds-only "podcasts" like https://www.bbc.co.uk/programmes/p0llbylh?

Real BBC podcasts have an RSS feed, and that does contain <pubDate>
elements, so I could follow the parent PID to get to them. Sounds-only ones
don't. :(

Dates are shown in the HTML page episode and series pages, e.g.
https://www.bbc.co.uk/programmes/p0nbzkt0, but they aren't present in the
corresponding JSON, e.g. https://www.bbc.co.uk/programmes/p0nbzkt0.json.

Thanks.

Mike.