innjan
You need to ask for the UC85 if she had a face to face assessment or the UC85A if she did not. These should list the points recommended by the assessor.
What was the Decision? Fit for Work, Limited Capability for Work or Limited Capability for Work Activity?
Have you got a copies of the UC83(a) and UC83(b)?
You can also ask for a written Statement of Reasons from the Decision Maker but if they are saying you already have all of the information then this may not be produced.
Yes, failure to explain the Decision should be accepted as Good Cause for the MR being Late.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
