SOLVED. Y/A book from early 70’s girl named Meg, takes place in England, engaged to a man whose sister doesn’t like her. [s]

[Mrfezziwig]

This story takes place in England, possibly Cornwall, somewhere by the sea.
A girl named Meg is engaged to a man whose sister takes a dislike to her, but acts nice to her face. Strange things start happening to Meg, like a rat is under the gas pedal of her car one night and she almost drives off a cliff. Meg might me an orphan; can’t remember. She is a ginger and when her fiancé gives her a ruby engagement the sister says “ you can’t give a ruby to a gingerknob like Meg. Thanks for any help-been looking for this for years!

[Kym]

Night Fall by Joan Aiken?

Checking google books, there is a reference to a rat in the car.

[Mrfezziwig]

Wow, that was fast! That’s it- thanks so much!