I've only seen one report for Corfu and that was with a 2.4m Channel Master offset dish, they still couldn't get BBC and ITV. Up in Kastoria on the Mainland North and slightly East of you, someone is receiving patchy reception of some of the Astra 2D channels BBC etc, but not 24hr. http://www.astra2d.com/greece.htm .
You will probably need a 2.8m - 3m dish, but that isn't guaranteed to produce the goods.
i receive all horizontal frequencies from astra 2d 24/7.I live in veria 70 km west of thessaloniki and i use a prime focus channel master 2.40 with quad lnb invacom 0.3 and Thomsion sky+ receiver.No vertical freqs.All the other channels from sky 24/7.