'Wish You Were Here' by Lesley Grant-Adamson (Hodder & Stoughton, 1995 ISBN:0-340-62871-5)
The general story is this: A woman, Linda, takes a holiday on her own and lies about her destination (England). One day, she meets a nice man, called Tom Hoby, in the hotel she is staying in. The next day he has trouble with his car and she helps him. This is the start of a relationship but Linda keeps her doubts.
Tom seems a obsessive guy and he takes care of many things: for instance he has the keys of her car, he posts her mail (not!) etc. He talks her into taking a trip with him to Scotland, to an island where he was born. One day, Linda finds a photo-album in his bag with pictures in it of 7 other women (he tells her twice that he "collects people", yeah right and no bells ring at all!).
So, in short, Mr. Hoby seems to be a serial killer and Miss-I-don't-know-how-to-handle-him follows meekly. Absolutely not convincing. Everything goes just too easy.
The only nice thing about this book are the two tenses, one present and one future, which keep a little excitement in the story. But once you have solved this puzzle even this is not sufficient.
The back of the cover has some very positive remarks about this book, e.g.: