Hello, my name is***** am a qualified lawyer and I will be assisting you with your question today.
Is this assessment organised by the employer?
That is what they have requested the tribunal to order
Unless they have any more specific evidence or arguments as to why they believe the original report is not valid, they should not be seeking a new one. This is not a case of trying to get reports until they find the one which is favourable to their case. If you were diagnosed by a competent professional able to give such a diagnosis, then this report should be accepted, unless they can show that it was flawed in any way or incorrect and they can show why they believe that is. This is what you should try and oppose their request on