You have one month to apply for a MR from the date of the decision letter, which is why we recommend you apply for a copy of the assessors report 2-3 days after you have an assessment as there is a small window for you to write to the Decision Maker if there are any inaccuracies with the assessors report, but you will need to be quick.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems