Just an update for anyone who's interested (I hate it when a thread leaves you hanging).
I had a physio appointment this week, and she gave me the thumbs up to start running again despite some lingering swelling/pain. Advised that I stay on the flat/even ground for the next month and then go to a follow up appointment. I've tucked a few 5k's away - amazing how hard even they seem after two months out -and hopefully I'll make a fell race or two before the year ends.