Well the other day I bumped into this thread at random: Location of Golden Dawn’s Horus Temple in Bradford, in which someone asks where it is, and someone else produces one of the best “Just google it” answers ever seen.
So I stuck the query into Google, this lead to this page The Desecrated Temple of Horus of the Golden Dawn in Bradford, which linked to these videos of the insides. Now this is quite interesting, although I seem to recall seeing a suggestion somewhere (in a comment on youtube?) suggesting that this isn’t the actual GD temple but a related organisation, either way people were doing ritual magick there until the 50s from the suggestion of when the paint was last renewed.
The search also found this: The New Society of the Golden Dawn in Bradford, which is the blog of the new GD temple that people are trying to establish, including a video of the history of the GD there, quite an interesting summary.