They've just given you the ISP's administrative centre for that block of IPs. The ISP would not give you the client's address . Client could be anywhere in Norfolk, or possibly further.
I didn't ask for the clients address as I have already said that would be unethical for me to do so.
I did ask my friend which DSLAM that particular IP was connected to and was informed the town in question is Norwich. This particular IP address is in Norwich - end of story. No confidentiality has been compromised, and publically available information could lead to a similar conclusion. All I have done is move my position from 'reasonably certain' to '100% certain with no room for doubt' - this is now a fact.
You should understand I didn't call 0800 Customer Service - I emailed a friend who works for the ISP - he checks with his network techies and tells me the answer. If the answer had been Inverness, Timbuktu or whatever I would have posted that.
Move on jeffro - I love what you write about 607 etc - just know that I am competent to comment on consumer broadband networks, and I am sufficiently well connected in the UK telco world to find out stuff like this if and when I want.