Greetings, Jules123, and a warm welcome to Rootschat. It's always fun to find a new cousin.
Your SANDYS ancestors include Edwin SANDYS, Archbishop of York (d1588), co-author of the "Bishops' Bible" of 1568 and Sir Edwin SANDYS MP (1561-1629), treasurer of the Virginia Company - a key figure in the settlement of America and an irritant to King James.
My Basil SANDYS was the son of my 4xgreat-grandfather Edwin George SANDYS (b1764) who was the brother of your John Percy SANDYS. Their parents were Nehemiah SANDYS and Elizabeth RYVES.
I don't want to spoil your fun in researching this extraordinary line, but I have much information so do contact me if I can help.
All the best
Philip