When does a house need re-wiring ?

[ppuch1]

One point i would make is while this is a complicated subject do bare in mind people like me are home owners and not in the trade. Can i suggest where possible the use of plain english and explinations of acronyms used.
Although i appreciate that some people resent the de-mystifying of trades

No one resents "de-mystifying "of the trades.
You can look up all acronyns in the FAQ... it's there to save typing so that you get your question answered more quickly.

I agree with the others that your best course of action would be to have a PIR (Periodic Inspection Report) carried out, if nothing more than to satisfy you that everything is ok.
But make sure if you do this get a reputable Electrician and ask for references.