Hi Colin123456
From your post I am not sure if you were 64 when you were awarded an indefinite award.
What usually happens is the DWP will contact you up to one year before your claim ends, unless you were given a light touch review, light touch reviews have only started this year, the light review form is, I am told is very simple, although I have not seen one myself. It would be good to hear from any member who have received a light touch review form.
As you are already in receipt of PIP before you reached state pension age then your claim will carry on.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems