Neither the pilot nor the current API appears to include all fuel stations, but at least they provide (hopefully) more reliable updates from the ones that do.
I'd been playing with the pilot study data and set up FuelBelly to aggregate and compare https://fuelbelly.com/explore?lat=51.50740713124398&lng=-0.1.... (doesn't include the API updates, yet...)
A quick play with the API, the information responses (opening times, addresses etc.) doesn't appear to be working, I just get a 500 (HTML not JSON) response. But the price calls are working, and I'm glad this is being pushed forward post-pilot.