Quite often claimants who win at a tribunal will not be sent a review form before their claim runs out, some claimants will receive a review form or claimants will receive a new claims form.
What you need to do 6 months before your claim ends is contact DWP to see if you will be sent a review form or a new claims form. I usually advise claimants to ask for a review form to see what DWP say, but do not leave it too late to make a claim.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems