We go next summer flying with Thomson, and the same date flight for this year only has 2 seats showing left on it and has done for a while now. I think middle of summer holidays is a gamble, BUT if you are willing to go indirect or fly into another airport as pps have suggested, you might manage.
You don't say how many seats you need? - this should also be a factor. There are 6 of us next year so I wouldn't have hung on for that reason.