I am a U.S. citizen. My daughter is attending St Andrews in the fall semester for a 3 year doctorate program. Her children are US/UK dual citizens but their father lives and works in UAE. I am planning to go to St Andrews to help my daughter with child care. I am retired with US based social security income. I understand that I can travel to UK on a tourist Visa for 6 months. Can I extend my tourist Visa in order to be there to provide childcare to my grandchildren beyond the 6 months. If it is possible, what steps should I take?