BATTERY DISCONNECT SWITCH CUT OUT 2 Keys | eBay
Brought myself one of them
Then made a hole in the front of the battery housing area under the passenger seat - so that the end you turn on & off sits by the passengers feet.
Then a simple thing of battery one side and car the other side.
All done and dusted worked fine Very easy install. You can put it anywhere though just dependant on how love your battery lead is. There are other options on the market but it ment removing my seat every time to engage power.
Hope that helps.