BBC Proms has occasionally released OFFICIAL CDs. And those are widely avail. for DL. Not sure whether any avid archivist has preserved FULL-FIDELITY programs -- audio and/or both audio/video) for EVERY year ... and has these programs avail for file-share download. This is different from (or superior to) the stuff on YouTube.

As an example, LOSSLESS-quality files of the 2011 Proms Film Music would be good to have:

https://www.youtube.com/watch?v=9KmLxiX8ZTw