It’s tucked inside the grounds of the Royal Family’s secret retreat – but Frogmore Cottage will soon become one of the most famous homes in the world. Prince Harry and Meghan Markle are leaving west London and moving into the 10-bedroom home, near Windsor Castle, to raise a family in a quieter setting amid alleged “tension” with Prince William. The Queen is giving them their own pad on a Windsor estate – Frogmore House – that’s been a favourite royal hideaway for more than 300 years and is home to a royal burial ground. The Grade II-listed cottage is said to be undergoing a multi-million pound refit, paid for by the taxpayer, before pregnant Meghan gives birth to the couple’s first child. Kensington Palace confirmed the move on Saturday, saying Windsor is a “very special place” for the couple. The Duke and Duchess of Sussex, whose due date is in the spring, will move into their main official residence early next year once the refit is complete. It is claimed that they had planned to move into one of Kensington Palace’s main apartments, next to William and Kate, but there has been a “bit of tension” between the brothers. It…