Thanks to Warren Ellis for the link to this - the other parts of this documentary are also available on Saxondaleroscks' YouTube channel.
It's called The Modern Antiquarian, and basically involves Julian Cope walking around ancient British archaeological sites talking about megalithic culture. Cope released a book of the same name, which this series is based on. There's also a brilliant website you can check out.
I loved this section, about Maes Howe and the other ancient sites in Orkney. As a kid, I used to come here every summer with my family. Our connection to the islands is on my Mum's side - her grandfather was the painter Stanley Cursiter. Stanley actually cast some silver jewellery using a sketch of the Maes Howe dragon, carved into the wall of the chamber by the Vikings. This and other Viking and pagan sources were a great inspiration to him in his painting and architectural design work.
Below are some photos of sketches Stanley did for a lithograph based on the Norse pantheon of gods, and for the carved chairs used in the back of St Magnus cathedral.