The Seventh Tide by Joan Lennon (http://www.joanlennon.co.uk/)

Joan Lennon talked about her books at my daughter's celebration ceremony for completing the summer holiday reading challenge and we instantly started working on her Wickit series, these are set in the Fens and much of it reminds me of my childhood home in and around Cambridge. We have completely fallen in love with Pip and Perfect.

The Seventh Tide is for slightly older reader and was written by Lennon when she first moved to Scotland from Canada and was living on the West Coast. It is full of terrifying stories of selkies and brimming with mythology and adventure, very well written although a little less fulfilling for me than the Wickit chronicles.