This is the earliset with the spelling Vanston I can find on FreeREG;
www.freereg.org.ukJohn VANSTON married Ann LEA of High Bickingham Parish, 21 March 1707/08, All Saints, Alverdiscott, Devon
Using the Soundex Option we find under VANSTONE the earliest are;
BAPTISMS;
01 Jun 1620, VANSTONE,Henry, Great Torrington, Parents JAMES/AGNES
12 Jul 1573, VANNSTONE, Thomasyn, North Tawton
11 Jul 1582, VANSTONE, Rychard , North Tawton
10 Apr 1584, VANNSTONE, Alson, North Tawton
All have Father GEORGE
There are Marriages in 1628/1670 which seem to be the earliest on there + Burials 1636/1644/1650.
So looks like they were around in Devon for a long time
