Goofs ?

Why is it a 'goof' or an 'error in geography' for Sloughborough in the north of England to have been shot at Hammersmith in London ? Isn't that what location filming is all about ? I doubt if the audience leapt up and said 'Look - that's Hammersmith!'
For all we know, Sloughborough might be a mixture of Hammersmith, Manchester and Bristol.
It's hardly a 'goof' ... 'Goofs' happen when Roman Centurions are seen wearing wristwatches.