The question of why the 47 has a left-side PIC comes up often. People want a Definitive Answer, when there really isn't one. If you look at pictures of the original Bell Model 30, the pilot sat directly in the center. The early Bell didn't have a conventional collective. Bell went through some odd control setups before settling on the "standard" we've come to know and love. Before getting into helicopters, Bell primarily built single-seat fighter planes. Fighter pilots fly with their right hand on the stick and left hand on the throttle. So that's the configuration Bell engineers adopted for the helicopter.
When provisions for a passenger arose in the Model 30, they sort of "piggy-backed" him on the right - very strange and awkward. As the model 30 design advanced , it got two proper seats, with the PIC on the left, which must have just seemed logical to the designers. As commercial sales ensued, the wisdom of left-hand PIC was demonstrated, as you could stick *two* pax in the cabin. (And don't forget, back in the early days there was no "adjusting the QNH" or any of that silliness. Helicopters
maaaaybe had a radio...but helicopter pilots didn't like using it.)
Out in California, ol' Stan Hiller designed *his* helicopter (the Model 360) with the PIC seated in the center, like the Bell. Why? Because the very weird overhead control came down into the cabin directly from the swashplate and that must have seemed like the place to put the guy who was going to be moving it. When the 360 morphed into the Model 12 (and a more conventional cyclic control arrangement was designed), the PIC stayed in the center, and two passengers were put on either side of him. When flight instruction was desired, dual controls were grafted on to the left-hand seat but the PIC stayed in the middle! Thus, the very weird seating arrangement in the Model 12/H-23.
Modern 12's can be set up for the PIC to be in the center or the left, but the same cannot be said of the 47. As others have noted, the fuel shut-off is to the left of the left-hand pilot. The cyclic friction is on the left stick. While some 47's have the starter button on the instrument panel, early models (in the days before electrical starter solenoids) had a foot-switch that pulled a cable that went to the starter. This foot-switch was on the left side of the center tunnel (or console, or whatever you call it). Later models had a box on the end of the left collective that contained the landing light and starter switches. I'm not sure if solo right-seat PIC in a 47 is prohibited or permitted. Those early RFM's were pretty...well...sparse in information.
So to answer the big "WHY?!" question that people seem to obsess over: That's just the way it turned out. You want to carry three people in a small helicopter? PIC has to go on the left. Works for the 47, the Hiller (basically), Enstrom, Hughes 300 (and 500) and probably some I'm forgetting. In modern helicopters, where the fidgety pilot feels compelled to let go of the collective all the time to adjust this or that...well...he should probably be in the right.
On Facebook, two guys, Paul Faltyn and Joey Rhodes host two separate sites dedicated to the Bell 47. They're both incredible, generous people with fantastic knowledge of the type that they're willing to share. If you're into 47's (and who isn't!) both of their pages are the place to be.