No printed music I’m afraid (although that’s often wrong anyway!)
When I learned it I watched the low quality video below. I can hear the bass quite easily on it. Although he’s miming, look at JR’s fingers during the instrumental 4 bars after the “hurry hurry hurry” bit. I see a sliding double-stop if not a triple. The whole thing is typical Rostill, punchy, bouncy and imaginatively syncopated. It contributes greatly to the rhythmic effect, one of the reasons BB liked working with him so much.
When I learned it, I used computer software to raise the pitch by an octave - which really shows up the bass part - and slow it down to two thirds, which gave me something to practise along with while I was getting the hang of it! This may not survive the copyright police but I’ll give it a go …
https://soundcloud.com/user763816310/in-the-country-bass-highlightedAnd here’s the video:
https://www.youtube.com/watch?v=y7A2IAXjSTU