There is no such thing as an individual "pilot seat" in an aircraft with two front seats both fitted with a full set of flight controls. It is perfectly legal for a PPL to fly from the right hand seat if he wishes, and to put his passenger ( student or otherwise) in the left seat
Unfortunately, there most certainly is.
Please have a look at the certification regulations concerning the positioning of the primary flight instruments etc with regard to the line of sight of the pilot while sitting at the controls and looking forward.
If it is something small with the instruments mounted centrally then you might have some hope but on the average PA28 or C172, the prossicution will ask you why do you think that the manufacturer clustered all the instruments switches etc on the left side of the aircraft? Would it be to conform with the requirements for these to be in the line of sight of the pilot and within easy reach? Can't be for lateral balance now can it?
Most light aircraft have a dual control column and pedals on the right because these are the minimum for dual instruction and for simulated IMC flight. Many don't have brakes on the right.
Like I said, you would find it hard to convince anyone that you simply sat your passenger in the left seat for comfort...........was it comfortable for you to be looking way over there for the airspeed?
The CAA issued guidance to RTF and FTOs regarding checking out FIs in the right seat and ensuring that they were competent from that seat following a tragic accident at Bournemouth during a trial lesson. Are you above all that?
Regards,
DFC