If I remember the EASA-OPS rules correctly, and provided they haven't changed, there was only a visibility requirement of 800 meters to conduct a visual. The normal caveat of visual with terrain also applies of course.
That said, in a place like Corfu I would definitely respect the circling minima. There isn't much terrain clearance as it is within the 4,2 nm circle and when you leave MDA there is none. Starting out below MDA cloud scudding. I like the creativeness, but no thanks.