Thought I'd just follow-up: thanks for the kick in the posterior regarding CGNAT. I got back to Starlink over this, together with other questions about IP address assignment, and they have now told me the report may have been wrongly assigned, grrr. What a surprise for me that is, not. So the case is closed and they said "donaworry" ;D. So I won't. I will still look into logging the CGNAT address just in case: the infringing IP was in their CGNAT block and not the external IP of the network, AFAICS. Thanks to all for the help. :)