GAME and Steam are / were the only companies allowed to sell the "Limited Edition" of Bad Company 2 in England (or so I read).
Anyway, I too ordered from Play.com (but it was delivered last Friday). My first "launch" of the game resulted in downloading around 300MB of "updates"; so I assume that you get the "VIP" content regardless of having the "Limited Edition" (as someone else said, Limited Edition just gives you a few unlocks from the get-go - which you can unlock from EARNING then in around 3 hours anyway).
Maybe "VIP" just means "not a pre-owned copy"? I don't know.
I have no idea what this "VIP" content was, but I do have "Arica Harbor" in my map list (and have played it). So if trogalicious is correct (in that map being one of the "VIP" maps), then you do get VIP content regardless.
And yes; there's only one Serial (at the back of the manual) for the "normal" version of the game.