Escalating a UC complaint to a senior manager

Does anyone know of an address to write to? I made the initial complaint online and it has simply vanished into the internet and got no response. I want to put something in writing this time so I can send it recorded delivery and have proof they’ve received it. However I cannot find an address to escalate to a senior manager (not the ICE - this is the step before).

I spotted that they’ve removed those details a few months back. I think it was Noel O’Hanrahan last time I escalated a complaint but that was years ago now.

If you email Theresa Wootten, District Manager for UC and JCP services in North London, you should get an acknowledgement from her PA.
https://www.gov.uk/government/publications/local-partnership-opportunities-with-jobcentre-plus/jobcentre-plus-service-leaders

when I supported a cl to make a UC complaint over the telephone and was not provided with a ref number to allow it to be traced, I was informed by the call handler that the complaint could be accessed via DWP Right of Access
https://www.gov.uk/guidance/request-your-personal-information-from-the-department-for-work-and-pensions

Thankfully UC responded to the complaint so we didn’t need to go down this route but maybe helpful for others?