1. be blonde, skinny and fairly tall;
2. be famous enough to be well-known in Britain (actually, a British model/actress would be best, but I can use one of a different nationality if necessary);
3. not be known to have an especially scandalous life (at least in the early stages of her career) - so she'd be a suitable role-model for a "well-brought-up" young woman living in British suburbia in the time specified above. Dating rock-stars, etc. would be fine - I'm just not looking for Page Three girls.
I have a fairly major gap in my knowledge when it comes to the 1970s, so I'd really appreciate any suggestions!
Edit: Thank you all SO much for all the names you've provided! You've really given me a lot to work with!