I have a ankle sprain and I am on boots for 4/6wks. Please can you suggest ligament supplement foods to help ligament recovery.

Well balanced diet. Eat a well balanced diet. Drink plenty of fluids. There is nothing particular for ligament recovery.
Try E and C. Ligaments, like most connective tissues, are typically slow to heal. This can be attributed to the intrinsically poor blood supply. Some studies have demonstrated that both vitamins " C " and " E " can promote ligament repair.
Time heals all . Wounds. Your still in a normal time frame for ligamentous injury, i'm not sure any foods or supplements have shown to improve healing quicker......Ice helps, resting when single and support of the foot/ankle when standing.