- A bit late now, but for the future.
- I think you can report this to both the Police (but not via 999) and the local council.
- Park neighbours' cars very close to either side of the offending car, so it can't be moved without the owner knocking on doors asking for help.
Either way, I hope the masking tape had the desired effect.
Personally, I've always loved the approach of the Fire Department in America.
Parking in front of a fire hydrant is illegal, so they love fixing the problem like this.