Francis Hayman 1740-41 Shakespear engravings

I have come across some original Francis Hayman engravings of scenes
from Shakespear at a flea market. They are from the third volume of
the 1770 second editon of Sir Thomas Hanmer's Shakespeare's plays,
printed at Oxford in 1743-44.

They are in good condition but unfortunatly the volume they came from
was so well used it was in many pieces and pretty much past saving.
It did have some rather intresting RADA notepaper taped insided too.

Anyway, all I can find on the value of these engravings are the
complete set of books which are either in private/museum collections,
for sale at about £8,000 to £10,000 or the laser copies available from
art print websites.

Does anyone have ANY idea of the value of the individual engravings or
know of where I'm likely to find out?

Any help would be most apreciated!

Colm