Here's a paraphrase of his explanation:
"She thought Chinese people were lucky. Whenever she saw one in the store, she would try to touch them
I couldn't help but laugh at the idea of this matronly British woman trying to more or less cop an (innocent) feel from a Chinese person. I figure maybe it seemed especially lucky as I doubt there were many Chinese people in a small town such as Bath (BTW, a lovely place to visit). Anyway, I'm sure there are millions of people in China who might not feel lucky all the time. I wonder how wide-spread this notion is. It could be a great excuse for a pervy guy with an Asian-girl fetish to pick up on a woman. Sorry, my mind always drifts to the darker corner. Well if someone ever tries that on me, he will find himself very UNLUCKY.