This is a subject that in my experience is open to a lot of debate, and causes quite a few arguments. If an installation was completed to an earlier version of the regs, then it isn't going to comply with the latest version and this is where the fun begins, it's all about the term "good for continued service" in my opinion. Lets say an installation was wired to the 16th and inspected to the 18th, now obviously, it isn't going to comply with the current regs, however if everything was in order and there was no risk to life and limb, then based on the fact that it did and still does comply with the regs in force at the time it was wired, I'd class it as satisfactory, although I''d be inclined to recommend improvements such as RCD protection for all circuits, as per current regs. However, as I said, this is where it is all down to the experience, and personal decisions of the person signing the certificate. A couple of years ago I had one hell of a row with an electrician, he'd inspected a premise and declared it totally unfit for use, a few months earlier I'd done some small jobs, changing a couple of socket fronts, iirc and had commented on how good the installation was, considering it's age, it hadn't been messed about with and in my opinion was good for continued service, along comes this bloke and virtually condemned it!
Somewhere, and I can't for the life of me remember where, it actually used to state that when carrying out an inspection it should be borne in mind which edition of the regs it was wired to, in other words, if it was wired to the 15th, and was still, as was, then it was fine, make recommendations by all means, but the fact that it wasn't up to current regs shouldn't mean a failure.
