Yes, you can download the "eroute" app to see these locations. See links at the bottom of this article.
When opening the app, you need to select the appropriate card to pull the correct list of fuel stations. To do so, select "UK fuels" followed by the green "fuelplus" card. This is your network of sites.
Here's what the fuel card looks like:
For iPhone users: https://apps.apple.com/gb/app/e-route/id1250358020
For Android users: https://play.google.com/store/apps/details?id=com.radiuspaymentsolutions.eroute.uk_android&hl=en_GB
Your fuel card is accepted at more than 4,250 fuel stations throughout the UK - including major brands like Applegreen, BP, Circle K, Asda Express, EMO, Essar, Esso, Go, Gulf, Harvest, Jet, Maxol, Morrisons, Murco, Nicholls, Shell, Solo, Star, Texaco, Total, Welcome Break, and more. All of these brands access the full 5p per litre discount on standard diesel - It's just Tesco and Sainsbury's that give you 0.5p per litre discount, which is why we call them "emergency sites".