Isolating/Security switch for Quartz

[Jimo]

Today my ‘new-to-me’ Quartz arrived, originally sold in 2011 it has a button on/off switch and a live twist grip which worries me.....I also have a Powrbike that Sensibly has a key switch to isolate the battery, question is has anybody got a Quartz having a key switch? If so where’s it fitted?
I worry that if someone should tamper with the button switch while I’m in a shop - and the twist grip becomes live there will be a hell of an accident. I can see that a cure could be to disconnect the battery plug but I would rather not resort to this. I like the twist grip for its instant response but for me - but it seems to be a weak point in security on such a beautifully made bike.

 

[Jimo]

I’m trying to get an LCD unit complete with all wiring as was fitted to some of the later Quartz models so far without success as Bateribike tell me that they are unable to source the manufacturer as Fallowfield have gone out of business and been bought out in name by a newer company.
So now I have to find a company able to supply or refurbish the Quartz battery should it go awol. Any information would be helpful as in my opinion the Quartz is a most beautiful piece of engineering almost on my mantlepiece!