Thanks for all the advice.
We are between exchange and completing now, so the house is empty for the next couple of weeks. The whole house needs modernising and I bought the house with the intent and at the price to do so.
Is the periodic inspection like a survey for the electrics? Is this what you use a basis for deciding what other works need to be completed? For example would it tell me that the whole house needs a re-wire?
A periodic will give you a professional OPINION on the condition of your installation, it will take into account both safety and compliance with the current wiring regulations. It will give you the best platform from which you can make your decisions.
An electrician shouldn't 'tell' you it needs a rewire, but just give you the best advice (s)he can with the experience they have gained.
If the property is empty then I would advise that you consider the extreme amount of work that both a) require and b) want to have done.