Thanks Bookbox & girlguide.
The cemetery is not Bunhill Fields, which is the more famous nonconformist graveyard. It is Bunhill City or Golden Lane Cemetery. It was excavated in 2006 by MOLA and there was a paper written about it, but have not managed to get a free copy. The City Bunhill (or Golden Lane) burial grounds were used from 1833 to 1853 as a nonconformist burial ground.
Originally the site of a brewery, 1¼ acres was set aside for burials. In Holmes book of 1897 on London Burial Grounds, she commented that the site was divided; with one part now a carriers full of sheds and carts, the other the city mortuary and coroners court. The burial ground now lies under a school located alongside the Fortune Gardens.
cheers Barbara