Manchester Library were very helpful when I contacted them after I'd got the death certificate of my great-great grandfather, John Stevenson, which showed he'd died in Withington Workhouse on 6th June 1867.
The archivist looked it up, though their records added no more than that he'd died at 5:40 a.m. The volume is too fragile for them to photocopy, but they said if I went I could photograph it. Unfortunately the admissions book for that period is missing, so I don't know when he went into the workhouse.
But the link posted by gortonboy to the holdings makes me wonder whether it might be worth going to see if there's anything in the "cemetery reference book" too.