Thanks for all the suggestions. I've now found a copy for sale at Past and Present Books of Coleford. They have a good range of Forest related books but don't seem to have a website. You can find them on ebay though at http://stores.ebay.co.uk/pastandpresentbooks/Forest-of-Dean-/_i.html?_fsub=7431735015. Worth a look if you are interested in Forest history.