2004 Peugeot 307cc Seat ratchet?

[Agile]

For some time the passenger seat ratchet has not been locking the seat.

However the driver's seat is also not locking now.

Probably something simple like a pen jammed into it

Any tips on what to look for and how to find the cause?

 

[carmanmemoranda]

A torch and a look under the seat, watching the mechanism