I can't imagine how the tail is still intact! - I did exchange one or two emails with Colin Green at A.B. several years back, but believe the factory shut their doors couple of years ago now so now lost that connection, and I didn't have a private number for him.
Unlike most of the other factories for which the books carry images of backstamps and labels, A.B. seem not to be included in the same way, so can't off-hand suggest a route to assess label age.
I think the mouse must have been one of the few creatures that Wedgwood didn't make.