When I was browsing through the Wish app on my iPhone, a shopping app tailored to the things you like, the exact same dupe sunglasses came up for £3 and £1 postage and packaging. I ordered them March 1st 2016, and received them on the 24th March 2016. They of course came from overseas, China I imagine, like most items on Wish do and 20 working days is about the average for items from there to the UK.
Obviously, for £3 I am not expecting a direct replica.