Keeping a record

I saw somwehere in the excellent guides of a form for a record list of phonecalls you make to dwp, who spoke to time and date and written letters sent time and date. A friend of mine is going through the run around with the dwp amongst many others and advised her from that to do that, and keep all copies of letters with proof of posting. Wondered has anyone else seen this form and whether they found it helpful to prove to DWP if need be contact when and where, if have to show an appeals board.

Thanks Gordon, i thought i had seen it, thanks for your response