This film is just a kids against evil genre. Thunderbirds is just the hook to get people to see it, but are almost incidental in use. The fact that the action takes place on Tracy Island is just a ploy to pull in the public. It was interesting to note what the film makers view of future London will be and how the World all fits together.
The best part of this film are some of the lines delivered by Lady Penelope which are highly comical. These provided some light relief for those expecting a rerun of the TV series.
Having said that it passes 90 or so minutes in a 'fun' way and so may just be worth watching.