Thank you again, I have modified all the jobs to run on a full week/daily differential with 2 week retention on the week and 1 hour retention on the day.
My disks are still full and I am yet to witness this DLM kick in to create some space out of the older backups. It kicks off tonight at 11pm so I will have to wait and see what happened.
edit: I'm now getting a "The requested media is not listed in the media index and could not be mounted. To add the media's catalog information to the disk-based catalogs, run an inventory operation on the media and resubmit the Catalog operation."
I'm reading two articles regarding this and neither are making too much sense, I'm not sure how to pinpoint what is missing - I assume it could be something DLM just removed (I finally got some space back now).
I tried: 4. On the right hand pane remove the check mark for "Use storage media-based catalogs."
Unforunately I am still getting this error on both storage disks.