Sockets Wired To 2 Circuits Simultaneously - Is this normal?

[PrenticeBoyofDerry]

could you upload pictures of these cables at sockets and at CU?

 

[ban-all-sheds]

I think the confusion is because these are single sockets, all others I've changed are doubles so did still have 2 wires but going into separate terminals.

No, I don't think that's why there's confusion.

The singles have 2 wires going into each one terminal. To confirm though, the single sockets definitely have 2 of each, 6 in total, wires coming out of a single grey sleeve. If I had decided to change them to doubles I don't know how I'd know which ones to use for which side, surely they could mismatch. Luckily decided to replace with single faceplates.

Err....

Back of a 1-gang socket:

Back of a 2-gang socket:

 

[ban-all-sheds]

could you upload pictures of these cables at sockets and at CU?