Not surprised, probably all ISPs do this, even in the US if you use their router
As other commenters have noted the solution is to use your own router. My previous ISP provided a combo modem- WIFI router they managed. I connected my router to theirs, thus making my LAN invisible to them.
I personally know more people using their ISP supplied router than one they purchased. Most people aren't boffins and are clueless as to how a router or any of their internet do-hickeys work. They will call their ISP for any problem with their LAN (Ipad can't connect, wireless printer won't print, etc.). I can see how the ISP gathering information on their LAN would be useful in troubleshooting.
Sound off - how many people do you personally know that have purchased their own router versus those using the one provided by their ISP? For me about 80% fall in the latter category.
Biting the hand that feeds IT
