The answer is probably staring me in the face but I can't see it.
Jane appears on the 1881 census RG11/ Piece 2077/Folio 48/Pg 8 as a 10 year old daughter, so b/c/1871, with her parents William (Thomas) Best & Agnes Read.
William & Agnes were married 1872 Tisbury so after Jane's birth. I cannot find Jane's birth reg as either Best or Read - wondered if someone else might have more luck.
Regards, Pheno