You are in a tough area too in terms of getting a place. How much maternity is your TV thinking of taking? My advice, get your name down as early as possible at as many nurseries that are vaguely suitable - they all want a deposit, but it it worth the initial outlay in my experience.
Are you guys doing NCT classes? If so, I can personally recommend the one held upstairs at The Old Nunshead.
At least you're right on top of the hospital, assuming you're going for Lewisham.