Sorry, a little confused. I Thought from the below reply it was more about creating jobs rather than a USP?
"Apols Justin. I would rather employ British nationals........
Our production/manufacturing end of things has really died away and we need to help those that live here play a part. Not contract everything out as most do. "
You can have "Printed in England" on it if you wish. "Created in England" is another option. Have had to do this with previous customers in UK.