Hi
The burial guide on the Rootschat London and Middlesex boards highly recommends viewing the London Burial Grounds website since it gives details plus modern photographs (not of any surviving gravestone which are usually very few in central London churchyards) of surviving churchyards.
e.g.
'There were no less than five other grounds made use of for the parish of Stepney at that time.....'Descriptions of the churchyards in the 1830s and 1840s just before they were shut on health grounds as they were overwhelmed by the number of burials that were and had been for decades occuring in them.
'STEPNEY. - The burial ground adjoins the church, and is crowded to excess; footpaths cross through it in every direction. The soil, largely imbued with the products of putrefaction, is also extremely moist; many of the tomb-stones have sunk deeply in the earth. Here the peculiar putrefactive odour may be frequently distinguished, - as indeed it may in many of the burial places I have described.'If the family were of substance then a burial could be afforded with more dignity and more permanence (reburials on used ground and charnal houses were in common usage in churchyards) with an erected gravestone which in the passing time period will mostly likely been cleared away as churchyard land was lost to roads, railways and other developments and what remained laid out as public garden. In the case of Stepney churchyard the V1 rocket exploding in the churchyard in 1945 won't have helped.
http://www.burial.magic-nation.co.uk/bgmileendold.htmBy the middle 1850s nearly all burials in central London were in the large public cemeteries that had begun being built from mostly the 1840s onwards.
The burial register for Robert Dunnett states he was of Mile End Old Town so more likely he was not buried in the actual churchyard of St Dunstans but one of its additional burial grounds which by the end of the C19th no longer existed.
Regards
Valda