Work capability assessment - mobilising (activity 1)

I have a DWP submission for one on my clients for ESA under the new activities. he is a leg amputee and walks with crutches. He often cannot wear the prosthesis due to sores and infections on his leg stump.

He has scored 0 points on the mobilising activity as DWP state he could use a manual wheelchair - even though he has never been provided with one.

What arguments are there in respect of “if such an aid can reasonably be used”?

As a side thought - has the DWP got a side line going to get commission from a wheelchair manufacturer every time they find someone scores 0 points as they could use a wheelchair ..??