I'm only adding this because its Steve Recommended.
https://www.mre-empire.com/
I've never ordered from them and have no experience with the LLC.
That said, they're based in the (post-BREXIT) UK and you should anticipate some random hassles with Customs, due to what's being shipped.
Also understand, modern MREs tend to stay shelf stable for
only a couple of years even if stored in a cool, dry environment.
Stuff that's on sale at 90% off, there's a good reason that's easy to figure out.
Bon Appetit and BOMBS AWAY!