You can do allmost all on electricity with the PHEV when you have a usage profile with relatively short trips. My commuting distance is 25-30km one-way and i can recharge at work.
I logged all my trips in the PHEV Watchdog app in january, in total 1269km from which 1144 on electricity. My EV score was 90.2%
It could have been better with higher outside temperatures, because the engine starts more often when the heating is turned on. To prevent this I drove often with the heating off which is no real problem when pre-heated and the heated seat on.

Below you can see my score of January and December. The Dcember score is most likely a bit lower because of two longer trips of 120km.