Map? I'm not aware of a map, per se, however there is a Memorial Inscription list that you can access on this site. I "mapped" the cemetery on graph paper, using the Memorial List....seemed very easy. However, once actualy on the ground at Christchurch, nothing is where it "should" be. I successfully located my family graves by using the list and (any) unusual gravestone as a starting point. It just takes time, patience and perseverance...but it's possible. Good luck and beware of large holes!
Christchurch Old Graveyard
http://www.forest-of-dean.net/?Forest_of_Dean_Records:Christchurch_MIs