Searching through things to find citations of Rob Dingle (Powys County Council’s National Trails Officer for Offa’s Dyke), I found this
https://www.yourdog.co.uk/regional-guides/offa-s-dyke-path
And that he had been on the BBC’s Country File
https://www.herefordtimes.com/news/9036787.bbcs-countryfile-visits-offas-dyke-path/
So we will have to take ArchaeoDog (Dougal) and take up the challenge, following the same walk.

Or we could start from the Offa’s Dyke Centre and go from there.
Here’s one of the Outreach visits that helped make the film
Citations: