Hi
As a Spanish property owner, I would most strongly advise against rewiring to UK standards. Although under EU law, it APPEARS to be compliant, convincing the Spanish authorities WILL be a completely different kettle of fish. (they seem to be a law unto themselves irrespective of what EU law says!!!!!!)
In the UK, we use single-pole circuit breakers. In Spain they are all double-pole, (because the German Schuko plug is un-polarised). We use twin and earth cable, where the earth cable is smaller than the L&N and un-insulated. In Spain, all conductors are the same size, and are all insulated in the appropriate colour and run in flexible conduit. (there is no grey "wrapping" around cables in Spain, they are all singles.)
We use ring circuits fused at 32A. Spain uses Radial Circuits fused at 16A. Spain also allows sockets in the lighting circuit, which is rated at 10A, whereas in the UK it is 0nly 6A. (there is no easy way of differentiating between sockets on Alumbrado (lighting) or Otros Usos (16A Power)).
Oh, in Spain your monthly standing charge (as you are probably aware) increases with maximum demand. The lowest (and thus most common) is only 3.3KW or ~16A!! In the UK we usually have at least 63A coming in!
