After installing and running TWD on a separate machine this morning, I allowed Steam to restore Cloud files on my main machine. Turns out that these weren't from my laptop, but from 5 hours' worth of gameplay ago (looks like I've not been in sync for a couple of days).
I've had a snoop around and a quick Google and from what I can see, all of the 'Rewind' saves are intact. These are the ones from last night around midnight (23:58) - at which time I was near the beginning of Episode 4. However, prefs.prop was last modified this evening, following my fated cloud sync. Now, in game, I am only able to continue from the middle of Episode 2.
My hope is that the fact that the rewinds are intact might mean that there's a way to recover my progress.
Attaching the results of the support tool. Can anyone help me out?