I did 10 qualifying flights and elected to use Montpellier - Genoa - Rome as my qualifier.
Subject to weather you could try Le Touquet & Ostende, log 2 new countries as well as complete your 300NM.
Or fly in a staight line (landing twice), overnight & make a weekend of it, then have 2 to elect.
Whatever you decide, I would advise you to plan a flight of 350 - 400NM, then when you put in your paperwork to the CAA, there is a very safe margin of error, you don't want to do this again because the straight line distances were 299.5NM when measured in the 'official office'.
Genghis , as per last year when I got my fATPL, it has to be in one day, 300NM or more, 2 landings away from the original point of departure - doesn't matter when you did it so long as you had a PPL.
It does not have to be a triangular flight, although many operations try to convince you it does.
That is why I had so many to qualify with.
FB