https://en.wikipedia.org/wiki/Vehicle_registration_plates_of_the_United_Kingdom,_Crown_dependencies_and_overseas_territories#Standard_plates Might be a Guernsey plate.
Wendi, I can't go over and knock at the door and say, 'Who are you?' I'll give it a few days and see if I can catch them, out in the garden. Surely, they will water the garden.
Hi Tilly I didn't mean to be as blunt as that . Just say that you were concerned as you knew they were on holiday . Ask if they needed any help as where to go for outings if they are from France or wherever .
When my neighbours go away they always let us know and tell us who will look after their property etc we check for them water their plants etc, how well do you know your neighbours do they let you know what is happening when they are away
Luxembourg registration plates sometimes only have numbers and the car will be left-hand-drive. Is there a small letter "L" at the edge of the number plate?