Thx for info gents - just ordered one !!I have one. It's free, so even if you don't use it, no loss. All it does is instead of having an account with each of the networks, they forward the bill over to octopus and they put it on your electricity bill as "EV Charging: Roaming on the Electric Juice Network -£X.XX"
The price charged is the same as pay as you go or standard rate. (at the moment, osprey has a discount on there app price, so if you want to save 5p/kw then use app)