Shambles how far does it go on electric ?
Mine's the HEV not the PHEV, so it's charging itself most of the time until it switches to EV (electric vehicle). I believe the PHEV can reach around 35 miles before it reverts to hybrid.
When it switches it seems to do around 3-4 miles (motorway driving, but dependant on load) before the EV turns off. After that, it may decide to switch to hybrid style (petrol+electric) for a while before running on whole petrol.
I would never currently have a pure electric vehicle as there aren't enough charging points on my routes.
The year 2040 (or, 2032 if Labour get control) will obviously change all that when petrol & diesel cars are banned.