On the next page in the 1881 census on the racecourse at Wilton is a Hughes family, headed up by Martha, married gipsy hawker.
Another Sarah Hughes in the family, age 22
A story in the Wiltshire Times, 22 June 1881 (Death on the Downs) about the inquest into the death of an illegitimate child, John Hughes, son of Sarah, a gipsy (is he the John baptized at Southbroom, 15 May?)
"deceased was the illegitimate child of woman of a gipsy tribe travelling about the country with her relatives, who had been camping out in lanes and on the downs."
Brief mention of another Sarah Hughes, also a witness at the inquest, and the aunt of Sarah.
Could that one be the Sarah in question?
Another similar case in the Salisbury and Winchester Journal, 31 October 1885.
Hampshire Chronicle, 14 November 1885
Sarah Hughes, 30, gipsy, was indicted for feloniously killing John Hughes, her illegitimate child, aged (18?) months, at Burley, the 22nd of October
Can't say if that Sarah is, or is connected to either of the two in the 1881 report.