date letter and assay office don't match

[widdley24]

hi there, please see the attached picture, the date letter refers to the chester assay office where as the assay mark is birmingham, how is this so and if it isn't then what year is it????





http://i63.photobucket.com/albums/h132/ ... MG0433.jpg

[Granmaa]

Looks like Birmingham 1978 to me.

Miles

[widdley24]

thanks miles