Very little we have will fit an F cup I'm afraid :( I wear a 34F - FF and I can't get into much at all here. As a general rule avoid ANYTHING with a wire, it wont work.
I'm wearing a UK 8-10 and can't get away with any of the plus size stuff as my waist is 26-27", so I just get drowned in fabric. If you're similar to me, you'll also find that the underbust is too big to give any support. I wouldn't opt for plus size unless you're at least a 38" bra back, but then you'll most likely find that your boobs won't fit in, but you can try!
Opt for things with either no defined bust or triangular or square cut busts with a generous empire cut (where the waist starts immediately below the bust). If it's gathered or roomy looking, give it a shot! We offer returns, so if it doesn't fit you can always return it to us.
Things I've found that definitely work on my proportions are:
Forplay Clubwear
Coquette PVC Halter corset
Coquette A-Symmetrical Mesh Mini Dress
Dreamgirl Charmeuse Chemise and Robe
Dreamgirl Lace Sleeved Chemise
René Rofé Lace and Mesh Halter Baby Doll (just!)
There are lots of other things that have no bust shape to them but stretch to fit. You should find things you can wear, just avoid the wires like the plague.