would the fact that my son was awarded pip mobility standard rate can move 20 metres but no more than 50 metres prove at a wca that he is unable to mobilise more than 50 metres on level ground
You can try and argue this fact, we have produced an overlap guide in the Members Only Guides called UC/ESA and PIP overlap.
To be placed in the SG he needs to meet one or more of the SG Descriptors, have you looked to see whether this is the case or note, the Descriptors are listed in our ESA Claim guide.