Books with title Twice Times Danger

HAVE YOU SEEN THIS GIRL?MISSING FROM HOME.DAISIE TREVELYAN. AGED ELEVEN. Becca and Daisie have been best friends for two years but their friendship has grown increasingly strained during the summer holidays before starting at different schools. Then Perdita turns up. Posh, bossy, rich Perdita, not Cornish like the others but a summer visitor, an emmet, and so identical to Daisie they could be twins, doubles - even Daisie's dog Dracula has trouble telling them apart. And from the moment the two girls meet, Becca is an outsider, a stooge in their games of swapping identities. But what begins as a joke to fool Dita's au pair, becomes deadly serious when Daisie goes missing.Becca must solve this sinister mystery to prevent twice times danger turning into double death.