Next romance: Anna and Anisha (that's the new vet's name I think?). They can be competitively career-focused, out at all hours, sustain career vs contentment tension before at least one of them moves for a loftier position / they both slow down and have children - bit like early Adam and Ian then.
Anisha's going to get up to something with someone anyway - Alastair? Dan? Upwardly mobile Toby (no!)?
Adam and Ian to fail, then - either Ian goes to Edinburgh, Charlie walks into his bistro one day, discovers Adam's free, jets southwards, moves in and re-occupies his old job once Justin's used Rob to do all the dirty 'set up' work and he's become a reputational liability to Damara.
Or, Adam loses all faith with Brian / business takes a big downturn (longer term) and hikes off to Scotland.
Kirsty and Tom, eventually.
Doc Locke and Lizzie, maybe? Ifti / Lizzie / Anisha triangle?
Roy + someone dull who's rarely heard from - a junior Kathy.