It is streaming very slowly for me, but thanks to the person in Germany seeding the torrent :-)

https://archive.org/download/the-gbp-25-000-pre-amp-that-wen...

This video is great. One of the better uses of the Internet.

Google/YouTube/Alphabet should be doing everything they can to encourage high-quality educational content like this, rather than being party to suppressing it.

Just jumped into the middle of the video somewhere and, wow, that's very much a prototype-looking amp inside.

Any chance it's the music he plays on his turntable, during the last 1 minute of the video?

Shazam says it's Khruangbin - People Everywhere (Still Alive)

I watched the entire thing and the only item that seems even remotely like infringement is the service manual containing the Tom Evans name that Mark made himself.