Hi Dave,
The 14 weeks quoted online is the duration a reassessment takes for DWP to complete.
If your hesitant to ring, contact your local Citizens Advice Bureau or Welfare Rights. From what you originally posted, your PIP has a definite end date.
If your original assessment 3 yrs ago confirmed your condition was so debilitating your current award was warranted, and your health has worsened then surely your award would continue if not potentially increase if you are not already receiving the maximum for each component. I am aware however, how easy it is for me to make such an assumption without the worry of losing an award hanging over me. All the negative stories you hear automatically has people assuming the worse and its awful.
Please don’t leave it and seek some professional (independent) advice as you are within the last 6 months of your award.
Very best of luck Dave, take care.