I just put in an offer on a house and it was accepted. I too think that you should consider changing EA. When I was ringing the EAs to book viewings, one EA in particular would take my details and say he would ring me back in a few minutes to book the viewing. They never did. This happened quite a few times. So I asked someone else to book a viewing for me, as I thought maybe I was doing something wrong. The same thing happened when this friend tried to book a viewing. I also noticed that the houses that I had wanted to view stayed unsold for a fairly long period of time and then sold for Less than guide price when props in the area were generally going for at least the guide price.
If I ever needed to sell my house, I would not use that particular EA.
Good luck with your house sale.