RosieandherMaw
Don't forget who embroidered it in the first place.
Although commissioned by Bishop Odo for Bayeux cathedral, and the exact individuals who embroidered it remain a mystery, historians generally agree that it was likely made in England, possibly in Kent, by Anglo-Saxon women skilled in embroidery.
I don't think we could use that as an excuse for keeping it, though.
Using that logic we could insist on repossessing all goods made by British workers over the centuries and sold out of the country 
And, as far a Bishop Odo is concerned, England was part of Normandy, by conquest, so the 'tapestry' just went to another part of Normandy...