Ken
The first thing you need to do is to make a formal request for a Mandatory Reconsideration, we recommend that you do this in writing so that there is no confusion about what you are asking for. Have a look at the PIP MR & Appeal guide for more details of the process and template letters that you can use to make the request.
www.benefitsandwork.co.uk/help-for-claimants/pip You should contact the DWP for a copy of the assessors report, you can do this over the phone but we recommend that you follow up the request in writing.
As explained in other posts, we recommend that your priority is showing that you meet the criteria for an award first, do this wherever possible by referring to your medical evidence, once you have established that you meet the criteria you can then show where the assessors report is incorrect.
Gordon