I always thought it was left seat only PIC, or is it just a case of simply flying from the right hand seat and thats acceptable?
It seems to be the discussion is going off on a tangent which was not intended by the OP. To get back on track, no, there is no rule (except apparently in Germany) that says the PIC has to be in the LHS.
Assuming you can perform all the required duties, and there is no specific prohibition in the POH, you can be PIC in the RHS as well. Although the first time you fly from the RHS I would suggest you take an instructor along. Both the motor skills (swapped hand functions) and the sight picture is different, so you may need to re-learn to land the plane.
And yes, the PIC role can swap in-flight if that is necessary for some reason. It does mess up the balance between take-offs and landings in your logbook though.