Hi Piers, for me and pretty much in general the bass is the key and upfront instrument together with the drums (check out sly and Robbie), I can recommend having a look at Don Chandler’s videos if you haven’t seen them , he’s played with many of the top reggae artists over the years and gives some very good advice for all levels of players, he breaks down some nice basslines too, he’s the first person I contact when I need to know something, you can also download the backing tracks and tab sometimes if you look in the descriptions, I’ll put a video up to show you his channel