Don't know about LFAC but every time I've crossed the channel and landed at Cherbourg, the guy at the terminal with the uniform (not sure if he was a cop, customs or airport security) couldn't have cared less about licenses, medicals, aircraft registrations, passports etc, the only paperwork he wanted to see were the euro notes for the landing fee and off ya go ! Easy Peazy
Added: I'm a dual national also (triple if the SNP get their way) and both passports never left my flightbag.