Style.CSS Updates Not Taking Effect (W3 Total Cache/CloudFlare)

I have been trying for about 4 hours now to update my website but it doesn’t seem to want to play along!

I’ve updated my site numerous times in the past and have always been able to see changes made to my site relatively quickly (after purging cache and a hard refresh), but this time for some reason I simply cannot make it stick!

I have had some minor success, every now and again I will see my changes take effect but they will disappear when I browse around my site or refresh again.

Here’s what I’ve tried:
Overwriting style.css multiple times
Purging Cloudflare cache
Clearing all W3 Total Cache caches and clearing my own browser caches (in every order imaginable in case that made any difference)
Triple checked my code, definitely correct.
Put Cloudflare in development mode
Paused Cloudflare
Deactivated W3 Total Cache
Viewed site from multiple computers in different browsers with cleared cache.

I have run out of ideas. Maybe there’s something I can do from my host admin panel to help? I just don’t understand why I’m having so much trouble with this today when in the past I’ve always had changes to style.css take affect within a few minutes.

I have not changed any settings on either Cloudflare, W3 TC or my site that I can think of that would cause this issue. If anyone has any ideas that would be hugely appreciated as I think I am starting to go crazy!