Yup, turned out to be the 1845 engraving by Charles Knight.* Quite nicely hand-coloured though so have put it up Meg Poems.**
* http://www.themodernantiquarian.com/img_fullsize/42508.jpg
** http://megalithicpoems.blogspot.com/
Well I'll be danged. Just taken this out of its mount and blow me down there's a poem on the back. Have put it here -
http://www.themodernantiquarian.com/forum/?thread=23046&message=453881
but the original text can be found two thirds of the way down -
http://www.fromoldbooks.org/OldEngland/transcription/