Request #21

 My memories of it are pretty vague. The paperback cover featured a red-haired girl in a green dress. I believe it was about a teenager who moved to somewhere very green and mysterious, perhaps with castles…maybe Ireland? And there were always white swans on the lawn. I believe the girl’s name was Phillippa. I got it in a box of my older cousin’s stuff…in the late 1980s, so I believe it was published some time in the mid-eighties. Any help would be appreciated!  Solved by Lost Classics reader Kim Dreams and Memories by Lavinia Harris