The Doomspell. The Doomspell Trilogy, #1

In a blaze of light, rush of wind and scrabble of claws, Rachel and Eric are ripped through the wall and hurtled on to another world. Like thousands of other children before them, they have been snatched away by the Witch. But this time the Witch has met her match. Rachel discovers that she has extraordinary gifts: she can transform herself into a feather, or fly on an owl's back, just as the Witch can.
The Witch is excited she has found someone to use for her own evil purposes. But for the Witch's victims, Rachel is their only hope.'High fantasy, richly imagined and refreshingly well-written - an excellent novel.' The Sunday Times'Brilliant, breathless and filled with action from page one.' Kids Out'Gripping, racy, children have been fighting to borrow it.' The Guardian