do you have to have a battery cutoff switch for sva if so where abouts have you put it

No, but you need two forms of immobilsation, such as 2 electrical or one mechanical and one electrical.
Remember that it will fall foul of the projections failures unless you do what I did.
I encased mine in clear resin along with the transponder for my immobiliser:


Description

Description

[Edited on 14/4/2007 by nitram38]

Or you could put it under the dash so it doesnt have to conform to the radius regulations.