Infant kits are in the ttl store. Start from 12months, then 18, 2yrs, 3yrs. £35 for top, shorts and socks, and it's a cracker.
Word of advice, though. Buy it big. Really big. My 9 month old is in the 18-24 and it's not going to last the season, possibly til Christmas at a push, but I'm framing it for him when he's out of it anyway.