Hester Bateman Transitional Spoon pre 1784

Given this is i believe a transitional spoon between the Old English and Fiddle patterns dating back to pre 1784. could any one give me a general idea on how much the spoon may be worth has my mother in law wishes to sell it and which medium is the best to showcase and sell this lovely little spoon. thanks in advance.
PC131085.JPG
PC131084.JPG