Does the computer say no? Looking for case studies

I think this started when I got bored trying to get a client’s evidence registered a year or so ago.
JCP were dragging their feet, refusing to accept certain pieces of evidence etc. Not the first time, and having seen similar issues crop up numerous times I submitted a FOI request to try and get some clarity of how the UC IT system works:
https://www.whatdotheyknow.com/request/uc_it_system_user_access_rights#incoming-1873510

A year on, I’ve progressed it to a complaint to the ICO. DWP have confirmed they have the info, but are refusing to release it under 31(1)(a) of the FOI act - basically saying it poses an IT security risk.

So, as it stands I’m looking at arguing that the public interest in having (at least some of) the info released outweights the risks. Practical case studies from the advice sector would be useful. Examples of where you/your clients have struggled to get DWP to act on a UC issue, and where they have blamed it on anything to do with editable fields or actions they cannot perform on the IT system.
DWP have already confirmed that there are ’ no data fields that absolutely cannot be changed’, so if that has been cited at you, chances are you were just speaking to someone who lacked the proper access.

I imagine the main benefit would be knowing who you have to speak to to resolve a given issue. Knowing where you have to immediately phone the escalation line, rather than even trying the normal line etc.
Ideally also have something to cite where we are trying to get DWP to start the WCA process, refer things to CHDA, accept forms, evidence etc.