Bob and other interested persons:
I'm guessing the owner wanted it both ways.
Traditional Brit tourist setup with SA planetary gears and chain tensioner for local (flat) and wet conditions. And a sturdy mount for a Cyclo Standard Derailleur with wider ratios for riding in hilly areas.
Maybe he could only have one bike, but could be indulgent with two setups.
Todd Teachout
Hercules, CA