I just checked the Title register which says that the property was built in 1974, if it hasn't had any work done since then i would assume that would roughly be the standards that it was at during that time.
Guess won't really be able to gauge accurately until i maybe get the keys and open up one of the sockets to check what it looks like behind?
!974 fits the installation, so untouched since then, unless anything has been added.
If you are doing a refurb, worth while doing a complete rewire now, rather that disturb it all again later, if you can possibly afford it. As above, whether a complete rewire, or just a consumer unit upgrade - get one with a few spare ways in, for extras you may need add later.