uc benefits appeal

Dear Respected Mods,

I received a backdated mandatory reconsideration request outcome where the DWP decision maker cleverly back tracked the response to an earlier date . I was only made aware of this when I accidentally opened my account and found a note . I was then alerted by my Service centre about this note . The backtracked date is gone past a month but the period I was notified by the service centre falls within a month period . I am also awaiting the final document as the decision incurred a change in my overpayment caused by DWP error.
My question is I have several grounds of appeal but worried if I have gone past the appeal time period as the DWP decision maker back dated the McRn response . Can I appeal to the SSCS now?

Thank you
Kind Regards