Ceiling roses are common in UK properties. Typically, one was fitted in each room, located in the centre of the ceiling.
The flex to the lampholder will probably be brown and blue, as flex has been manufactured in these colours for decades.
Most installations of this age are overdue for replacement.
Some people use insulation tape to identify the switched live instead of sleeving. This has the disadvantage that the adhesive dries out and the tape then falls off. Alternatively, the adhesive oozes off of the tape, attracts dirt and ends up as a nasty black sticky mess.
There are also those people who don't bother with sleeving or tape. You will curse them the next time you find a ceiling rose where the switched live is not marked.