Looking for help with a name

My 3rd great grandmother Ann Sedd is reputed to have migrated from Cork around 1830, probably transported and possibly via Lancashire. Several documents, including certificates that had Ann herself as informant, give her surname as Sedd. However, there's no record of a female Sedd arriving in NSW. As these certs would have been transcribed from oral information from the informant, I'm wondering whether the name Sedd has been incorrectly transcribed, possibly due to Ann's Cork accent. I don't know which part of Cork she'd have come from, but some DNA matches point towards Millstreet as a possible area. I'm wondering if anyone familiar with Cork regional pronunciations would have any ideas about the actual surname? Thanks very much.