Wrong dates used for working out historical PIP

About a week ago, I had a tribunal for historical PIP mobility.
I was arguing that I was entitled to the mobility part in relation to the new rules on mobility and mental health. I won.

But afterwards, I re-read the papers (over 360!) and discovered that the DWP had written to me saying I wasn't entitled to PIP mobility from the end of February 2017 and my original request for an MR and then tribunal, showed that I was also arguing for payment from this date.

But, in the tribunal and in the tribunal's decision, it says payment from the end of June 2017, which is four months later.

I understand that there is something called 'a slip of the pen' that I can query, but this isn't exactly a slip of the pen, as the DWP gave the wrong dates in the tribunal.

My question is, do I write and inform the tribunal? Or someone else?

Thank you for your time if you read this.

Gary,

Thank you so much for responding. I will contact them tomorrow. Also, thank you for the phone number, and making it easier for me.

And thank you for the welcome. I think that part of the reason for my success in the tribunal last week, was having access to information on this site. I also think this site helped me succeed at tribunal in December 2019. As you might guess, I'm becoming a little tired of tribunals. (I have had to argue every single decision I have received, so far.)

Anyway, onwards and upwards and thank you again.

CVKDS