As to why you can't go, that is a contentious subject. If you call in at any port under Turkish control you risk having your vessel impounded by the Greeks if you go south.
A ridiculous situation which has, in parts been softened with regards to crossing the Green Line (unless you possess a blue beret, then you can come and go as you please). You can cross as a tourist easier now, but trading or mooring on the other side is verboten. If you wish to keep your boat.
Personally, I think the Turkish army should leave as well as the Turkish nationals. Then the U.N. should actually do what it was supposed to do, keep the warring factions apart. They failed in 1963 and this is the result. Mind you, other parties are as guilty for the situation. British Government, Greek Junta 1974, Grivas and successive Turkish regimes.
The ridiculous part of it is the last Prime Minister on both sides, Denktas and Clerides grew up together and married sisters!
So, back to the boat. It is registered in Jersey, Todora 2, I think. My binos weren't strong enough to make it out.