Vobster is about fourteen miles south of Bath, in the north-west corner of Somerset, just off the A362.
It is only a small hamlet, so you will need to look at the map carefully!
To find us, get a copy of Ordnance Survey map Sheet 183. Vobster is at grid reference 705493.
Alternatively Vobster is on Sheet 142 of the excellent Explorer series (same grid reference of course!).