The flat is excellently located, was cleaned to a good standard and was pleasant to stay in. Overall I would highly recommend and was good value for money! The below complaints are rather minor and I'd definitely give 5* if they were remedied.
Firstly the A/C was fairly poor - it was very hot while I was in Thessaloniki and the old A/C unit barely managed to keep the flat at a tolerable temperature. It was also very loud which was annoying when trying to sleep at night.
Furthermore the kitchen didn't have the necessities for actual cooking: no chopping board, knives or pans large enough to cook a meal larger than than one small portion.