So it turns out "Childhoods End" could be the real start of Arry playing whole songs with bass chords. He would go on to do this a lot on X Factor and beyond..
Found this interview all these years later
"I've always played with my fingers. There's only been a couple of occasions when I played with a pick, when I wanted to play something really outrageous—doubling up rhythm, say. On the new album [Fear Of The Dark, 1992], on "Childhood's End," there's like a chord thing where I play single notes on one bit and I overdubbed a bass chord as well. I started using a pick at first, but then I got rid of that, didn't like it, and I played it with four fingernails, almost like a scratchboard, which got the sound I wanted.
It almost sounded like a pick, but actually I was playing downstrokes across all four strings, strumming with my four fingernails. That was mixed in—playing like that, obviously I'm not gonna get so much weight on it, so I actually put single notes on played with fingers, and mixed them together, during the choruses.
If we do that song live, I don't know what I'm gonna do [laughs]. I'll probably have to play the part with the fingernails. I've found over the last few albums I've been playing more bass chords than ever, to get the weight. Like when the guitars break out into a harmony-guitar section, it leaves things open, so to get the weight I tend to play a lot of bass chords, usually barre chords, like strumming downstrokes, playing the four strings."