All modern cars that are homologated for towing have will have dedicated connector for a vehicle specific towbar wiring loom.
Mitsubishi do not make wiring looms or towbars.
If you buy a towbar wiring kit from Mitsubishi in the UK, you will probably get one manufactured by Right Connections UK Ltd and you will be paying a lot more for it from Mitsubishi.
The Phev towbar wiring connector is covered in black tape & somewhat hidden.
See below. (2015 model).
Hope this is of some help.