The best ones I have found so far are Marks and spencers. You are looking for BIG cup so lots of cover it will be called a "T-shirt" bra on the packaging. The best have a life of their own and stand up all by themselfs. These are what you are looking for, don't be afraid to feel them and make sure the cup which is a pre formed (hence why they stand up) is nice and thick ie 5mm plus any underwire are firmly were they should be. La sensa bras are **** and personnally think they make them to fall off after a few drinks. So don't go there.
I will keep my eyes open as I too need to re stock.
I got caught out last week wearing sexy number, I dared any one to shoot me! lucky it worked.