I think it is disgraceful charging worried customers £35 each to change travel plans following the unrest in Tunisia. Thomson have charged me to change my holiday because I did not want to "wait and see what happens". This trouble will not settle completely for some time and customers should not be punished for wanting to change plans. You should be ashamed of yourself Thomson!
I dont think its a punishment for changing plans. Its a standard charge which is in the booking conditions and most tour operators are operating the same approach at the moment.
When is your holiday booked for?