Hi Mary,

If you can't get her death cert from the local Cheshire RO, I think this is the GRO ref for her death:
Name: CORKHILL, Mary Ann
Registration district: Stockport
County: Cheshire
Year of registration: 1907
Quarter of registration: Jul-Aug-Sep
Age at death:23
Volume no: 8a
Page no: 28

Last year the price was the same when full index refs given, whether RO or GRO.

Sue