According to GF9's site, you can order these sets online or you can (or will) be able to get them from selected retailers.
If, like me, you live in London, England, you'll probably have to get them online. Theoretically, there are a couple of stores in London that (will) sell them, but GF9 obviously didn't do their homework. They just assumed that meant a London catchment area. It doesn't. Just because a store is technically in London, doesn't mean you can get to it easily from most of the city. I'm very lucky that one of the stores is a walking distance from my place, but if you're in the wrong part of town, it could take you 60 - 90 minutes to get to one of these stores. That may be a timeframe that's considered normal in the US, but not in the UK. Even if you can afford the time, the cost of public transport/petrol alone would put a lot of people off. There are stores in central London that sell RPGs. GF9 might want to consider selling to them as well.
Oh, you Londoners! You're so hard done by!