big thank you

Hello and a huge thank you to everyone connected to this site for all the help and advise you have given me in my puirsuit of my sons DLA claim.
Firstly he has retained DLA HRM and has been inreased to HRC from the lower rate.
Innitially we asked them to look at his personal care again as his mental and physical health has deteriated since Nov 2010. I wrote in April advising them due to his condition that it may be some time before the completed form would be completed due to his ill heath. They actually received completed forms for his motobility and care in May. All his eveidence pionted out that his situation started to deteriated in Nov 2010 and is still the same but his award is only backdated to april and not Nov 2010. Can we ask why it has not nbeen backdated to Nov 2010 as all evedence proves this was the case?
Whilst i am pleased his care component has been increased, but both components have only been awarded for a period of 12 months. His previous awards have all been for 3 years and the last award was for 5 years.
My question is can we ask why he only has been given 12 months this time around for both components. His motobility is certainly not going to improve and in anycase we did not ask for that to be looked at even though we filled that portion out. Do we have grounds for asking why etc or appeal the lenght of time given. I do not want to sound aggreived but im dreading doing this all again in less than 12 months time as its been very truamatic for all concerened.
Thanks aghain though as without this sites help it would have been very difficult to get this award.