One of ours was hidden under grass and it took a bit to find, so it may be there. Otherwise, we have a 50m tape measure, long enough to measure the front of your block, and our pegs were correct and so were the block between you and us. So come and knock on our door and we can measure it out from the other front corner peg, that way you may have an idea if it is wrong.
If any of our pegs were missing our builder would make us get it resurveyed. Hope it's just hidden.