Updating firmware using UEFI with Lifecycle Controller

I tried to update one of our R810 servers today using the UEFI with Lifecycle Controller and a local DVD SUU. I was following the instructions in a White Paper "Lifecycle Controller Platform
Update/Firmware Update in Dell PowerEdge 12th Generation Servers" from Dell. I wondered if you could identify what I was doing wrong.

 Here are the steps I took:

1. From Dell Repository Manager, I exported the latest system bundle for the R810 to SUU ISO and burned it to DVD. I started with Linux SUUs, but discovered this morning that the UEFI only accepts Windows DUPs so I exported and burned the Windows x64 system bundle.
2. I booted into the UEFI and selected Platform Update.
3. I chose the “local repository” option and clicked Next. The Custom SUU in the DVD drive was automatically selected. After clicking through the “catalog could not be verified – do you want to continue” message it presented me with the error: "No Update is available. Ensure Windows catalog, and Dell Update Packages for Windows are used."
4. I tried creating a USB repository instead, by copying all the files in the SUU/repository folder to a folder called catalog in the root of the USB drive, per the instructions in the white paper. That gave me the same message. I moved all the files to the root of the drive but that didn’t help either.

What did I do wrong? I even tried pointing it to \repository (for the DVD) and \catalog (for the USB) but it didn’t help. Was I using the wrong type of SUU? How do I point the UEFI to the right location on the DVD? Do I need to specify a file? What syntax do I use?

Thanks.

Regards, Dominic