If Go Daddy asks me, in a required field, what province London is in what is the answer?

Question

Basically I have to fill in a new account for a client and his business address is in London (I am not) and Go Daddy asks me what province London is in, its W1U6BS postal code/zip.

Answer 1

there is a city in the province of ontario- canada.could that possibly the place.

Answer 2

W1U 6BS is in Marylebone in the City of Westminster.

There is no such thing as a province in the UK