DDD (Degenerative Disc Disease)

7 years ago I had my 1st episode of sciatica but got turned away by GP on basis that can't do anything for back pain. Unfortunately 4 years ago I had a herniated disc rupture and I was finally taken seriously. MRI's show that I actually had both lumber discs herniated at same time. After this left me unable to walk and in incredible pain I slowly recovered but never back to as I was before. I have since found out that as well as these discs being herniated they are all degenerative. I now have daily back pain due to DDD. Has anyone been successful in getting the higher mobility rate on PIP for this condition or have any helpful pointers? I've just been told that there is nothing they can do for the DDD. Even though other counties in UK do offer disc replacements I've been told flat out that they do not do it privately or on NHS where I am so I've been left to face the info that I simply am going to have to live with it. (I can't afford to go privately outside my county) Any info anyone can supply is greatly appreciated