PIP Mobility Assessment - OA Knees

Hi all, I have just had my PIP mobility assessment by Capita. It consisted of:

Observed hobbling 15m from reception to chair and then 10m from chair to consultation room;
Take 3 - 4 steps from chair to middle of room;
Lift one foot off the ground (1 - 2 inches) and balance briefly on opposite leg;
Bend the knees and lower backside as if sitting in a chair (lean forward and stick your bum out!)
Take 3 - 4 steps back to the chair;
Whilst sitting in the chair, bend at the waist and touch your toes;
Observed hobbling 10m from consultation room to reception desk.

Despite having severe OA in both knees, with letters from Consultant Orthropod, Physio etc and filling in the mobility questionnaire stating that for 30 mins every morning I am incapable of walking any appreciable distance before meds kick-in, but can walk 20 - 50 m most of the time - all backed up with letter from the GP.

Despite all this, the DWP Decision Maker decided that I can walk 200m reliably, safely and as often as reasonably required without pain, discomfort or other hindrance on more than 4 days per week, because I can walk round my house and visit a supermarket - thus 0 points. I'm not sure how big they think my house is or if they know a supermarket where there is 200m between each item but... in short, an extraordinary conclusion!

Needless to say that I have asked for a mandatory reconsideration pointing out the current regulations and the DWP's own guidance to its staff; with of which appear to have been completely ignored!

Has anyone else been subjected to this rather bizarre and wholly inappropriate mobility assessment?

Gordon, many thanks; I have done so with the mandatory reconsideration letter.