Interesting. We too were diverted to Athens Sept 08 after a cracked windscreen on BA Thessaloniki - Gatwick flight. On that occassion plane dropped immediately to 10,000ft and we flew round for 1.5 hours to burn fuel before landing at Athens. Flying out to Skiathos on Monarch in May got same problem - cracked iwndcreen. this time we were 1.5 hours into flight & flight turned round and came back to Gatwick.
BA flight was Boeing & Monarch flight was Airbus.
Have I been unfortunate or are windscreen cracks a frequent problem?
I have flown about 3-4 times a year for the last 20 years and these two incidences are the only two times it has happened.