Ah, I see they changed the process.
A couple of years ago I submitted some paperwork to the CAA. That paperwork specifically did NOT include a change of address form or anything, since I did not relocate. However at that time the CAA did not need any reason or form to change an address. So they did.
Fortunately they only changed the last digit of my house number so all correspondence was sent to my neighbors. Who hand-delivered it to me anyway.
The good news was that after a simple phonecall, they undid their change. They even sent me the new license, which once again showed the correct address. All for free.