Hi Annie.
Normally when a passed over relative continues to visit then it could mean that they are around you to make sure that you are coping with the loss of losing them. The problem is that when they visit and then you in turn feel their presence then all the emotions of losing them over come you so its made very difficult for you to move on with your life.
As a rule when we sense passed over relatives over a long period then it could mean that they have something to tell you so you can both move on, because it is not healthy to dwell on the sadness and the loss.
In terms of making contact i would try and find a comfy place to sit, close your eyes, regulate your breathing, and when you feel yourself at your most relaxed imagine in your mind a room with 2 chairs. You need to sit in 1 chair and then you need to invite your grandad to sit in the other. Then in your mind just sit and have a conversation with him.
Note: When you do this, ask him about the pocket watch
Charlie.