Hi billco, I usually write to Ron, rather than Brian, as I don't think Brian has the day to day running of the site anymore.
The Cemetry index is done by Freda Chorlton, this is what it says on the Wigan Cemetery landing page.
"Many thanks to the Friends of Wigan Heritage Service, in particular Freda Chorlton for her hard work in producing this index.
Further information can be obtained from the Museum of Wigan Life."
It will depend I suppose on if it is a transcription error, in which case it could be corrected, or if the records are incorrect. if the record is incorrect, I don't believe it can be changed here, the record would need to be amended first.
Get an email to Ron, I'm sure he will be able to point you in the right direction.