I stumbled across the info on here.... my local agent denied it to begin with but I have stood my ground and have finally got confirmation that my flight is cancelled. Suggest you contact your local store and set the question to them - ask them to contact the programme change department at Thomson - they are the ones that confirm it.
Don't be fobbed off by them - it seems thomson are doing there best to not loose any sales and making it difficult for people to get there money back - when in reality that should be what is happening, unless you do want to re-book another holdiay with them. Good luck. let me know know how you get on.