If you consciously bought a PHEV then your rationale would have been, I can drive the car every day on battery (nightly charging) and only need petrol when I am doing a long distance drive. Or one day I have to make a longer run, then I have no range angst.
Then you are unlikely to be disadvantaged too much by RUC since you will only use petrol for the long drives.
If however, you bought the PHEV and then can't be bothered to charge it each night treating it as a ICE (I had read many users in the US do this) then you need to change your behaviour if you don't want to be financially impacted too much.