Robin Ellis, who plays Reverend Halse, starred in the earlier Poldark (1975) series as Ross Poldark.
The horse that Ross Poldark sits in the opening montage, as he surveys the sea, then gallops cliff-side is a 16-year old draft named Seamus. When Aidan Turner came out to select a horse, he originally did not pick Seamus, favoring a horse named Jonny Wilkinson, who is larger than Seamus, and "quite a goer", in Turner's words. Trainer Mark Atkinson felt that this made Jonny Wilkinson potentially unsafe, and steered Turner toward Seamus. Turner now says that if there is any romantic involvement between cast members on the set, it is between Seamus and him, with Turner continually petting and hugging him, and overjoyed to see him again after hiatus when a new series begins. He even sleeps on him - literally. "Between scenes, I sometimes have a snooze (while still in the saddle). We really are close..." Indeed, Atkinson has gone on record as disapproving of how much doting affection that Turner lavishes on the horse in case he should become spoiled. Atkinson says that Seamus responds well to Aidan because they are both Irish; says Turner, "(He) reacts to my accent."
Steel Rock referred to when mining is granite which is common in Cornwall.