Sue Bentley 
Magic Kitten: Double Trouble 

Flame is heir to the Lion throne but though powerful he is not yet strong enough to stand up to the evil uncle who is trying to claim the throne. Flame must hide in the human world as a kitten but can »t stay in any place for too long. Flame travels from place to place in various kitten guises using his own special brand of magic to help children who need it along the way…
Kim can »t wait for her cousin Mia and her cousin »s Siamese cat, Bibi, to visit. But when they turn up neither cousin nor cat are half as nice as Kim remembers and proceed to make Kim »s summer miserable. But when Kim discovers a tiny silver tabby kitten with emerald green eyes looking up at her in her garden shed, things seem to magically get better…