I have had the same symptoms and the same cure (not on my F-Type): battery connections that looked good and seemed tight. But the non-start issue was easily and quickly cured by removing the battery connection and cleaning both posts and clamps and refitting securely.

Occam’s Razor interpreted: having tried everything else, the most obvious solution is likely to be the correct one!

 

I haven't had the problem crop up again, but I now am keeping the necessary tools to remove and clean the battery with me in the car. I will also buy some of those shims too, seems like a good idea. And I am still keeping the portable jump starter just in case, plus I might need it to even get INTO the trunk. I'll call this resolved for now.
Thanks!