All the cable chases in this house have this metal cover on them. And they are all earthed with bare wire which has been clipped to the joists under quite a bit of tension in places! I'm guessing this is original to the house. But what edition of the regs would this have complied with? The house has been rewired in the 80s or maybe early 90s I think in DI singles so they could pull through these old chases. The original wiring was VIR and much of it is still present though dead. And for VIR it isn't actually in bad condition compared to some ive seen.
No safe zones either. I was merrily hacking plaster off the bathroom wall and I cane across one of these metal covers with no indication it was there.