She's actually part of my very first, very hazy memory of Emmerdale Farm. I had this vague recollection of a girl named Rosemary, no more than that. It wasn't until much later I got it confirmed that there had actually been a Rosemary on the show.
Her very first episode could be found on Youtube for a brief while, but it was taken down. But there are other episodes uploaded there now with her in them. Here's one for instance
Trivia: Her co-star, George Fenton, has gone on to become a famous composer, writing music for many acclaimed wildlife series produced by David Attenborough ("Planet Earth", "Blue Planet" etc), and also for many movies by Ken Loach. His breakthrough came when he collaborated with Ravi Shankar to write the score to the multi-Oscar winning "Gandhi" (1982)