Is it cheaper to charge a PHEV at a commercial charge point or using the petrol engine?

I own a Ford Kuga Titanium PHEV. Is it cheaper to charge the battery at a commercial charge point or by charging it using the petrol engine?

Is it cheaper to charge a PHEV or run it on petrol?

Now that we have a £2,500 energy price guarantee will it still be cheaper to charge up my plug-in hybrid electric vehicle (PHEV) or will it be cheaper to buy petrol?

How do you charge an electric or hybrid vehicle if you can't park outside your house?

Millions of owners of houses and flats are not able to park their cars outside their property. So how do they charge their electric cars? No article ever seems to answer this problem.