This is what they did with the one in 2005, seems pretty conclusive;
“Following a collapse of the shaft fill in 2005, the treatment involved part filling with clean stone from 32m below ground level, then concreting a section by tremie from 25m bgl up to 12m bgl; diagonal anchor rods were drilled into this concrete plug from four sides before constructing a reinforced concrete cap supported on 8 piles over the shaft.“
In 2007 this went on in what looks to be the area of the latest collapse;
“A geophysical survey of the rear gardens was carried out in July 2007 to locate this shaft, but was inconclusive. This was followed by shell and auger drilling and probe drilling. The investigation located a possible feature close to the rear corner of the house and monitoring of the semi -detached house was put in place, however the owner Home Housing chose to indefinitely suspend the investigation in late 2008 due to lack of funds available to remediate the feature.”
Looking on Oldmaps it’s pretty obvious that there were some serious pits in the area.