PIP - Mental Health difficulty not being accepted

My partner requested a PIP review in Aug last year as his walking was slightly improved. He had been enhanced score for both sections.
It took until December to get the phone assessment. It was difficult as he has depression and anxiety, and ongoing back pain so I was with him prompting the whole time and I had all the previous and current claims laid out to refer to. On the phone, they can't hear my prompting so at times I was able to speak with the assessor to explain things clearer (I'm carer).

We received the decision in January and they decided to only give Standard rate for daily living and nothing for mobility. They only awarded 4 points in moving around.

The bit we are most concerned about is when we requested a copy of the assessor's report, in the justifications section they almost always use 'no imput from MH services' as a reason to not recognise the impact of long term anxiety and depression on that activity (nor the need for me to prompt, support and encourage). In previous awards this has always been recognised, and even in the assessors report it refers back to reasons for ending his job partly due to anxiety, and that he has depression but cannot tolerate medications.

He cannot follow an unfamiliar journey without me supporting him, and he has to plan meticulously in advance and use a sat nav, sometimes with a back up sat nav and printed out google map directions. If the journey is diverted, he has to stop and we deal with the panic and reset the sat nav before we can continue the journey. Before an unfamiliar journey he has great anxiety and restless sleep, sometimes doing a dummy run if it is short journey just to reassure himself. It has happened that if a traffic diversion is required, he chooses to abandon the trip and return home. It is noted by the assessor that he has the mood disorder most days and does not connect socially other than with a therapy group.
I feel this level of anxiety and uncertainty should fall under 'Planning and following journeys' score (d). In the past I think this was the award given.

We requested a MR and we obtained a GP letter confirming his depression, anxiety and that he was unable to tolerate the antidepressant/anxiety meds due to the side effects. It took ages to get the letter and we did not get the GP appointment beforehand to give a current assessment as the GP said time was limited so she went from his medical history. She is his MH support, and he has had contact with the support team at the medical practise both f2f and by phone. I feel this shows MH service input. You cannot be referred to secondary MH services here until it becomes a serious care issue.
With the MR I referred them back to previous PIP records to support the long term nature of his MH condition even though he was not under a MH service other than GP and MH therapy group, even quoting one section of a past claim. I supplied the GP confirmation. I also expanded information on the activities they had not considered the MH imput fully.

The MR decided that they were sticking with the original score.

We are now at the point of considering a tribunal... and whether it is worth it as it will cause considerable distress to someone who has severe anxiety and social fobia.
We have to continue to appeal as he reached pension age in March so we would not be able to begin a new claim. This is his last chance.
The loss of his Blue Badge will make unfamiliar journeys almost impossible as finding parking and managing payment is a contributing factor.

Is it worth us pushing for a tribunal? Would his condition seem to justify the higher score for Planning and following a journey? Does the information I have given here sound reason enough to go through that distress?

I already went through all the site info when preparing his MR so I thought I had done enough to support his claim using this site's recommended phrasing and references.
Thank you for any advice you can offer.