Posted: Thu Mar 14, 2024 11:08am
The rules are that EU citizens can stay a maximum of 90 days in one visit but, if they wish to stay longer, they should register as an EU citizen. Just like when UK was in the EU, nobody bothered and nobody checked. The only snag would be staying longer than 6 months. The 90 in 180 does not apply to EU citizens and you could go to another country for a few days and then start the 90 days over again but it really is simply to go on the register and just tick the non permanent residency box.
Your having a UK passport is a misnomer as you can't switch between passports. Your UK one wouldn't have a stamp showing when you entered so, if you used it to leave, it might look like you've been here forever.