The maps I've been using to identify the Tabram location left much to be desired, but they were the best I could find at the time. In the course of triple-checking my coordinates for Tabram, I found an extremely useful section of an 1894 Ordinance Survey map which I didn't find previously using the same search terms, so it appears to have been posted recently. The great thing about this map is that is shows the location of the lodging house where Tabram's body was found, and major streets which still exist today. So, this allows the location to be determined on modern maps by transferring ratios of distances between reference point from the old maps to the new maps.
I've had a detailed map of the vicinity of the lodging house for quite some time, from which I cut the above drawing of the lodging house, and it allowed me to determine the location of the stairwell (the elongated X in the lower half) where Tabram's body was found. Since I haven't been able to determine whether the location was at the front or the back of the building, I took the average. I zoomed in on these maps as much as possible, took careful measurements with MB Ruler, transferred the resulting ratios to Google Earth, and arrived at coordinates of 51.516804°, -0.071781°. This is about 18 feet to the north of the previous coordinates, and about 16 feet SSE from the Guilford Ghost's location. The map has been revised, again.