Janet
There should be no problem with you requesting the PIP report, phone the DWP office that dealt with your claim and make the request, I would advise you to follow it up in writing.
You can certainly reference the fact that you were assessed as only being able to walk 20m-50m for PIP, but please be aware that the ESA test is for Mobility so you would also need to show that you cannot self-propel a manual wheelchair over an equivalent distance to meet the ESA requirement. You do not need to use a wheelchair or even to own one for it's usage to be considered, as long as the DWP can show that any usage is reasonable it will be considered.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
