In Beast over Hammersmith, Bruce gives a really good vocal performance, but does not have nearly as much stage presence as he would in the future. He sings Hallowed be thy Name and Children of the Damned almost identical to the studio versions. I've only seen the segment of Beast over Hammersmith from The Early Days DVD.
I think that Maiden also got the footage for the Number of the Beast promo video there, I'm not sure though.