GP PIP Appeal

Frantically getting ready for Tribunal Appeal. Sent out the GP form as provided by this site, for evidence. Been GP for 20+ years. Just taken a call from the GP's practice. Apparently the GP feel she is unable to complete the form as unable to answer most the questions/points. No other reason - had offered to pay and sent an SAE. Just asked them to return the questionnaire with a note explaining reason for not completing. Has anyone else had this experience. What if any action did you pursue.?

Not actually for me. It's for my sister - she's a regular at GP having epilepsy, osteporosis together with her learning disabilities and and mhealth issues. GP knows her extremely well so was surprised by response. GP actually wrote 11years ago to SServices disagreeing with the plan to move my sister 'into the community' when she'd spent most of her life in one institution or another since she was 8-10years old (special needs boarding school and residential care) She's now 61 so a long time. Disappointed with response and curious if anyone else has had this experience. Can I presume that she would have replied in same way if contacted by DWP?

Oh well will battle on without GP assistance. Will do our best on the day. keep fingers crossed please.
Sister got the Daily Living after MRecon but not the mobility -going to tribunal on this From what I have seen/read this is the hardest bit. Seems it can be interpreted in so many ways. e.g Can walk 200metres. That's as maybe but how long does it take to do 200m? Does anyone know what criteria are set for 'in a reasonable time'??? From what I can see from google 'normal' is about 3 miles per hour. Any help here welcome