Welcome aboard,
The Cheetah V1 Adaptor is not included as part of the standard Radar Detector Interface for the V1 because most people don't need it. Why put the price of the kit up for everyone by an unnecessary $30?
You only need the V1 Adaptor if you are also going to use one, or both, of Valentine's remote display units.
The Cheetah V1 Adaptor is $29.99 and it lets either one, or both, of the Valetine display units work properly at the same time as the Cheetah display. This is what you need to get your kit going the way you want it, and yes, you can omit the Valentine Audio Adapter.
The only place to order the Cheetah V1 Adaptor at the moment is direct, on this page.
Order the V1 Adaptor for remote displays.
As regards testing it, the kit was actually designed to be fitted straight to the bike, quickly and easily. The reason you're not getting the system working on a bench is because you'll have connected our POWERSENSEnode to your bench power supply. As it says in the manual, the POWERSENSEnode is an "engine running" sensor. It actually has to be connected directly to the battery terminals and you then have to start your engine, before it will allow power to pass along to the jammer system. It's designed to make it much easier to fit onto the bike, because you don't have to cut into the bike electrics. It will not work on a bench power supply, because that's not a running engine.
If you're going to bench test it, you have to unclip the little oval POWERSENSEnode, then clip everything else together and you'll be good to go.
It's important to remember to hook the POWERSENSEnode back in for fitting onto the bike. It's what shuts everything down automatically when you stop the engine. (so you don't get flat batteries)
Hope this helps.