Peter Stone, "An interview with The Beatles' Chas Newby", Beatlology Magazine (September/October 2007), pp. 8-13:
"...CN:...but there were a couple of tunes where I had to learn a bass line. There's a Ray Charles number, Hallelujah, I Love Her So, but they used to do the Eddie Cochrane type version of it. And that had a more scale bass line to it, rather than just a blues .playing the prime note and the thirds. So I had to learn that. And the other one was Red Sails In The Sunset. Its funny now, because I've joined a band, here, locally -you know, a bunch of old guys playing together. And, some of the songs they sing are Beatles songs, and it's amazing how many of those Beatles songs have the same scale progessions for the bass lines. And funny enough, that's exactly the same as Red Sails In The Sunset. I can remember, even Paul must have, I guess, been listening for the bass line that he wanted in a particular song. And, I can remember him playing it, because bear in mind we were both left-handed and so we had a certain affinity. But I can remember him playing it on his guitar and then showing me the notes that he wanted me to play for Red Sails In The Sunset and Hallelujah, I Love Her So. But with all the others, there wasn't that sort of problem, because they were basically... 12-bar blues and just play the bass line like a boogie-woogie, like a left-hand on a piano.
P.S.: It's intriguing that Paul was interested, even back then, in the bass lines.
CN: All I'm saying is that he was the one who told me what he wanted to hear. Whether it was just the bass line or whether he told the others what he wanted to hear, I don't know. I'm not aware of that. But, he was the one in those two particular songs. He made sure that I knew what it was he wanted..."
So, Paul McCartney was playing bass lines with his Solid 7 on 17 December 1960..., wasn't he??