Well although I hate to go with the obvious, I have ordered three (very different) bunches of flowers lately, all from InterFlora and all three have been perfect. Unfortunately, they're one of the most expensive companies. One reason that flowers are "half dying" is if you've chosen an obscure company, which needs to travel a long way with them to deliver them... InterFlora has shops all over.
Alternatively, pop into your local Post Office (all of them should know what you're on about and provide details, even little village ones) and ask about Bunches. They're another good company, which could prove cheaper and just as reliable.