So by the look of it you & next door may have never been earthed, Very unsafe.
Well at least it is a bit safer now that the old VIR tails to next door are gone.
The best thing to do may be to have an earth rod fitted outside, & have a new spilt-load cu fitted with a 100mA Time Delayed RCD fitted in the new cu as the main switch, with a 30mA RCD for the sockets etc, This would then be classed as a TT supply
So then the things that do not need to be RCDed (i.e. Lights) go on the 100mA Time Delayed RCD, & the things which do need RCDing (i.e. Sockets) go on the 30mA RCD.