Do you happen to know which Westfield it was @exyle? We were at the Hammersmith one but there's one that was built for the Olympics in 2012 and that one's in Stratford.
If I had to guess I'd guess the Stratford one was bigger but I'm not sure. I didn't even realise there was a Westfield in Hammersmith until this weekend.
We mainly use them for cheap overnight parking! 😁