My father's mother's mother's mother was a Sarah Dorset who married a John Biggs on 20th February, 1843 at St Marylebone, Middlesex. The marriage certificate says that her father was a George Dorset. Witnesses were William and Isabella Dorset.
Unfortunately, I know little further about this surname.
FreeBMD (at present) provides three candidate deaths for a Sarah Biggs - but as yet I have not determined whether any are appropriate. FreeBMD does not as yet record a death for George Dorset.
If you provide details of your quarries I will keep an eye open for them.