Is it normal that both front doors can only be locked by using the key.
It is not possible to lock the passenger door from the inside , I suspect I may have a faulty locking mechanism but maybe not ??
I'm in Italy, things here don't work like the UK. Any request at a local spares shop is met with a shrug and a shake of the head.
It is easier to buy from ebay sellers in France.
For the Renault 4 GTL the doors could only be locked from the outside. The earlier cars (pre-1973) had only an exterior lock on the driver side. The passenger side was locked with a small lever from the inside. I guess the R6 was the same.