It's an interesting question.

I just don't seem to notice any more. but when we first came back to UK I did notice......so did my wife.

Firstly, IMHO all Filipina's look young. Some look very young. Much younger than their actual years.
Secondly, IMHO all Filipina's look beautiful.
Thirdly, Filipina's are significantly smaller (more petite) than others.
Lastly, despite the world getting smaller, interracial relationships are still of some interest to many. So, when the lady looks so young, petite and beautiful many folks want to take a second look, for all sorts of reasons.

Just my 2 centavos