Hi CC, welcome to the Forum !
You may have already found them by now, but there are a few websites offering old photos of the Forest, usually from period postcards.
This site is a commercial one if you wish to buy prints, their Old Photos may be found within this "Bygone Forest" Index among their various webpages.
http://www.forestprints.co.uk/bygone_forest_of_dean.htm

From that index under Drybrook there are a few showing the Hawthorns part of Drybrook.
http://www.forestprints.co.uk/drybrook_the_hawthorns_v2.htm

Oops, should have looked on this site first, here's a clearer image of this same area albeit from a different vantage point, and a few more too of course.
http://www.forest-of-dean.net/gallery/drybrook/pages/page_35.html

Hope this helps a little.