I’m slowly rewiring my current place. I had 4 sockets daisy chained together. Luckily upstairs so not running anything of any decent wattage, but still a risk.
Personnaly I would not feel safe using that socket if you think it isn’t earthed. I’d disconnect the wire with only the live and neutral and then test if the socket you think is a spur is working or not, with the plug tester. Especially if the socket is in a kitchen. Also if it is a metal faceplate, with no earth get it switched to a plastic one.
random thought, did you have any up lighters in the house? Only time I’ve experienced wires with no earth are on lighting circuits. Someone could have taken a feed from the socket for a wall light.
sounds like you should probably get the place checked over. One sign of a bodge generally means more hidden….as I’m finding out…