This is really interesting! Interesting to know the undercurrents that are influencing things, the problem with reading something episodically is that you can forget whats happened not so long ago.
Tommy Sheppard might be an interesting figure that you could play with. He was a member of Labour for a long time, has the money and connections to finance his own election campaigns (Frankie Boyle and Kevin Bridge's donated money to his SNP deputy leadership campaign) and has razor-sharp political instincts (one of the only SNP MPs I met who predicted the outcome of the 2017 election). I've always thought that if the Brownites had been slightly stronger in the Labour party he might be high up in Scottish Labour by now. Hell, he might have even won a seat in the 1992 election depending on your PoD.