Regarding the flying-from-right-hand-seat-rule. not sure what the law is in uk but the regs and insurance providers in australia state you can fly an aircraft solo from the right seat providing you have access to all controls and displays. As stated b4 most single pipers are hard to fly right seat due to fuel selector location.
the above doesnt count if the company's ops manual rules otherwise.
ps there might be other reasons for it, but ive seen solo pilots fly from right seat to practice gripping opposite controls for instructing and aerobatics.