If I am to have an extractor fan and spot lights fitted in the bathroom I am right in saying the person doing this needs to be able to issue a Part P certificate?

YES absolutely otherwise you as the householder can be fined up to £5000. Check the references of the electrician you employ very carefully and only pay for the work once you have been issued with the electrical certificate and have the online building regulations notification reference number. On average I see about 3 - 4 people every week who are ripped off by unregistered installers where the work is substandard and there is no certificate, or its ok and have been told the certificate is in the post etc.

Actually the information given here is incorrect. Although you will need a minor works certificate, it will not need to be registered under Part P any more if it is outside the zones (2.25m high in this case) and is not a new circuit. Nor is there any requirement for it to be 12v. However it must be "suitable for the environment" so a good IP rating is highly recommended for a bathroom. I hope this helps.

Please only use a registered electrician, ensure all fans/lighting is of the correct IP rating or 12v, ive seen so many lash ups in atttics etc of down lighters please dont pay until a cert is issued, it wont take long to test a fan and lighting, you should get a minor works certificate.