Hiya congrats on the pup. I too am picking up my DDB pup this weekend. We've been advised by the breeder to keep out pup on a rawfood/biscuit diet. You can purchase frozen blocks of fresh raw natural meat for around 50p per Ib. It comes in many different flavours for variety and is 100% natural with no added rubbish.
Heres their website
http://www.prizechoice.co.uk/
We will then be adding a very small amount of biscuits for the added nutriets and oils needed. This is one of the best diets for this kind of breed. Ive been doing a lot of research into it and can definatly see a difference between a dog who eats raw, and one that doesn't and its definatly for the better.
Cant wait to see pics!!!