Seven seas of Rhye, see what a fool I`ve been, God save The Queen

Seven seas of Rhye, see what a fool I`ve been, God save The Queen as the video in the concert at Hammersmith Odeon 1975. How do you think there is a possibility, the chance of the existence of these video records in this concert?

listen to the audio...you will get your own answer:
from what i recall, Brian says somehting like "i think we're alone now" ....the cameras were off