DWP got terribly behind with ESA reassessments and suspended them for several years. Many people had their date pushed back as a result and it is possible this is what happened in your case.
Nothing on this board constitutes legal advice - always consult a professional about specific problems
Thanks Mrs.Hurtyback. I remember asking two years ago re my ESA assessment and they told me then I was awarded until Nov 2016 because of the backlog [I had already recieved ESA for two years by 2016..So I really have never heard they award ESA of being four years without further assessment I thought there was very little backlog now.I am not complaining just surprised to get it for four years. .