Nine years ago we lost our younger son to cancer. Nine months ago his widow, our daughter-in-law, sold her house and moved with her two daughters, now 11 and 13, to Belgium to live with a man who already has a wife (but may now be divorced) and three children – two boys (14 and 12) and a younger girl. He came to live with my daughter-in-law some time ago. Since then we have had no direct contact with our grandchildren even though they were less than an hour’s drive away. Before his arrival we used to visit weekly, take and fetch the girls from school, etc so their mother was able to be at work on time. Since then, apart from a card thanking us for Christmas presents and a birthday card, neither we nor the other grandparents have heard anything despite sending letters and emails. Our worry is for the girls’ welfare. How can we ascertain that they are OK?