Need some clarity on the appeal process

I am helping my sister appeal a PiP award. She has a stage 2 brain tumour and stage 3 breast cancer and herniated discs which need an operation. We have just had the decision letter of the mandatory reconsideration and nothing has changed so we need to go to appeal. I have typed up the appeal in great detail doing the 7 steps mentioned in the appeal section on this website. I have listed out every descriptor and detailed what score was given, then what score I think it should be then what the decision maker stated in their reply and then our argument for what the decision maker did not consider. It has come to about 11 pages. It includes the introduction and the history and conclusions. I've copied the format form the appeal section on here. I haven't got a copy of the Health Professionals report because we didn't know we could have a copy so technically I am putting a case together blind. We initially went to a McMillan benefits adviser and she wrote the mandatory reconsideration for us but didn't know I if we could have a copy of the HP report so we never asked for it. But we have checked with my sisters consultants and GP and they have not been asked for anything so from what I gather they have used the Health Professionals report only. I have now sent a letter today to the DWP asking for a subject access request as detailed on this site asking for all their documents used in coming to their decision. I cannot wait for all that to come as they have 40 days but I must submit an appeal now. We're not using the McMillan advisor to do the appeal as her knowledge was quite limited but I didn't know this until we met her. The only thing I'm not clear about is whether I submit my 11 page appeal document with the SSCS1 form now or whether we do a brief sscs1 form and save our 11 page appeal document for the tribunal hearing. I know at some point the DWP will have to provide us with their tribunal submission but I think this isn't until after the tribunal date has been set. Any help we'll be greatly appreciated. Thanks.