I don't like limiting beliefs; but on the other hand, we have to recognise the general truth that English girls are less receptive and will flake more if you're gaming in London.
To not recognise this may lead to a false critical analysis of your game, as it happened to me - I thought I did things wrong when I had great instant dates and D2s with English girls but they flakes MUCH more than foreign girls. Now, I don't see anything wrong in my game, just that English social convention makes it generally less socially acceptable for girls to be telling her friends that she is seeing someone she met on the street.
So, don't let it stop you gaming local girls and don't assume she'll flake but IF she does, it may be something totally out of your control so move on.