I just read Mick Wall's book Hammer of the Gods. As a Finn, I obviously read it in Finnish. In the end of the book, there is interviews about the gig in Helsinki 1970. Famous finnish musicians talked about the gig, they praised Zep members and etc. BUT what really made my eyes pop out was that the interviewer said the gig was pro shotted by the Finnish TV company YLE. He said the footage is/was black&white and he don't know if the tapes do still exist. But what I do know is that YLE had a really bad manner to wipe old tapes and use them again... For example, Jimi Hendrix's gig in Helsinki 1967 was wiped. The possibility of pro shotted footage from Helsinki 1970 still exists, it's not confirmed by the Finnish media that the tapes were used again.