Ignore any comments re: ESA appeals. They are constituted completely differently to PIP panels and always have been.
At a PIP appeal there are 3 panel members UNLESS it is an appeal that concerns a failure to attend a face to face. Although it has been ruled that should also be a 3, HMCTS are inconsistent and often list FTA cases in front of a judge sitting alone.
The usual routine is that you have a judge, a medically qualified person and a "disability qualified member". The judge will be 10 years post qualified. The medical professional will be a surgeon, specialist or consultant and the DQM is a person with experience of disability. They could be disabled, a carer, a social worker, even a welfare rights officer.
Your summary decision will just list the members of the panel. It is likely that anyone listed as Mr. or Mrs. will be a consultant as they do not use a Dr. prefix. So, no, unless you have some concrete evidence to back up your claim there is no error of law there at all.
The 5 errors of law are
1) Breach of natural justice.
2) Insufficient findings of fact.
3) Perversity - the findings of fact don't support the subsequent decision.
4) Getting the law itself wrong - using the wrong reg. etc.
5) Taking into account irrelevant considerations.