Hill of the Angels by Sue Mayfield

Hill of the Angels is set during the English Civil War. Twelve-year-old Abigail Booth is the daughter of sheep farmers and textile workers; Grace Fowler is the daughter of the parish priest. They become friends and climb together to the Hill of the Angels, a rocky outcrop where, according to local legend, light creates a pattern of angels on the cave wall. Abigail and Grace meet there and bring beautiful gifts for the angels. However everything changes as the English Civil War breaks out and the families of Abigail and Grace find themselves on opposing sides. Separated from each other by warring ideologies and religious sectarianism, will their friendship survive and will they ever meet again at the Hill of Angels?