Rather than buy a mandolin (which would only probably cost £50-£60 second hand) I decided I'd take the cheaper option and tune my acoustic guitar like a mandolin (open G in this case I believe).
This discovery, combined with my recent obsession with Green prompted me to record and arrange this in one two hour session - sounds impressive but it really is quite easy as the song is basically the same riff looped four times. The bass part is the same three note pattern played all through the song.
I'm actually really pleased with the results despite the fact I know it does sound like an acoustic guitar and not a mandolin!. Plus, I'm always really fond of songs that come together really quickly rather than others where weeks of tweaking are necessary.