I've made some good progress on my current story today. I achieved it by going backwards.
I've been working on a new draft of my current story but had been struggling to fill in a lot of the gaps. I looked through some older drafts (I keep everything for each story contained in a separate physical folder) and found a much shorter version, in a first person perspective that felt like a much better read. On going back over that version I fond that a lot of what I'd written since could provide material for the gaps in that earlier draft.
So I've gone back to that earlier draft, gone back to a first person perspective, and I think I now have everything I need to make this story work.
Hopefully I should have a new draft finished this week then it's time to re-write, re-write, re-write.