I have done quite a bit or research concerning the records of Axbridge Workhouse.
The Sarah & Joseph SAMBOURNE who were resident in Axbridge Workhouse in 1841 were from the parish of Burrington.
Sarah SAMBOURNE died in Axbridge Workhouse 25th Jan 1844 and was buried in Burrington Churchyard 29th Jan 1844, aged 17 or 18
Joseph was still in the workhouse in Dec 1842 but was advertised as "ready to go into service"
Another Sarah SAMBOURNE died in the Workhouse 6th March 1870. She was buried in Axbridge Churchyard; she was 84.
I'm not convinced that these were necessarily related to the ones at Long Ashton.
These burials are also at Burrington
28 Apr 1819 Sarah SAMBORNE 59
15 Jun 1821 James SAMBORNE 57
17 Feb 1825 Mary SAMBOURNE 64
With best wishes
Pat