Rank tried to build Ronald into a star, giving him the lead in a thriller, The Secret Place (1957), alongside Belinda Lee.. On British TV he was in Salome (1957), El Bandido and the TV series Hour of Mystery in an adaption of Night Must Fall. He appeared regularly in Armchair Theatre over fifteen years and other British anthology dramas.
He had a good role as the bad brother in Robbery Under Arms (1957) and was a villain in The Wind Cannot Read (1958). He was in Schiller's Mary Stuart and Ibsen's Ghosts on stage in 1958.[7][8]
After a TV production of A Tale of Two Cities he supported Hardy Krüger in the Rank comedy Bachelor of Hearts (1958),[9] and was in The Cloak (1959) for TV and a production of Miss Julie (1959) at the Old Vic.[10]
Ronald had leading roles in Conspiracy of Hearts (1960) for Rank, playing an Italian officer helping some nuns, and The Full Treatment (1960) for Hammer, directed by Val Guest. Hammer kept him on for another thriller, Taste of Fear (1961), which was a big hit. So too was Mr. Sardonicus (1961) made for William Castle.
Ronald had a support role in the comedy Twice Round the Daffodils (1962) and was back in the lead for Jigsaw (1962), a thriller directed by Guest.
Ronald had support roles in Billy Budd (1962) and was the romantic lead to star Juliet Mills in the comedy Nurse on Wheels (1963), made by the Carry On team. He had the star role in two costume pictures, Siege of the Saxons (1963) and Hammer's The Brigand of Kandahar (1965).