I hear the XC40 is exceptionally thirsty.
The B4-P petrol one certainly is compared to its peers, but the PHEV one seems to be very economical. In one group test that I read the Ford Kuga PHEV was the most economical by some margin (against the XC40 and Peugeot 3008 PHEV’s) but I don’t think that anyone on this forum has taken delivery of one yet (unless I’ve missed it).