I think the problem is that Jilly's hair doesn't seem to have a style, it just hangs. I think that very few women can get away with straight, long hair with a centre parting. It really is one of the harshest, most unflattering ways to wear your hair and imo only works on extremely good-looking, youngish people (men included!).
Although Jilly is pretty, she's not a beauty and she's not that young and I think the style is doing her no favours. There are lots of ways to style your hair without having to resort to a short cut. A really good hairdresser could work wonders on her hair, if only she'd let one near her.