
It's perhaps also rather a strange idea for a children's novel to pit schoolkids against a real terrorist organisation (ETA) particularly as they seem woefully ill-equipped. In an implausible scene, in order to make a copy of the terrorists' bomb instruction manual, they have to use a photocopier at the local library! The ending of the book suggests that the children will have further adventures, but now we will never know what those would have been.....
Incidentally there are telepathic twin girls in this story - but they're named Maureen and Brenda, not Gill and Gail!