Not that big a difference, actually, according to the Internet.
Nou camp: 106 x 70 metres
WHL: 100 x 67 metres
Only 18 square metres bigger. Probably the camera angle then. Or that by playing as crappy and congested as we do, we create an optical illusion of a tiny pitch.
Entertaining game, by the way. City doing well, ruffling a few feathers here.
The calculation is length x width so 7420 - 6700 = a difference of 720 square meters as it goes...