I originally posted asking about the door lock on my mates Peugeot 309 (he was unable to open the offside door) after a lot of banging pulling and pushing of handles we eventually managed to unlock the door.
We then removed the door panel, inside door handle, solenoid, and lock barrel, unscrewed the window channel and after a great deal of very fiddly manoeuvring managed to remove the complete lock assembly, which we then gave a good soaking in petrol and lubricated with oil, all of the mechanism then operated like clockwork.
However (full of confidence) after re-installing it, we then found that we had exactly the same problem as before! So after dismantling and examining everything again, the problem was eventually traced (after its removal) to the outside door handle, which had a spring loaded lever on its rear that had rusted up and wouldn't return to its original position after the door had been shut.
Giving this a good clean and lubrication so that the spring returned the lever after every operation, and then going through the tortuous procedure off reassembling all of the fiddly bits again, everything worked beautifully.
All in all a swine of a job, but something which would be much more straightforward after having done it once.
It's also a fair bet that spraying copious amounts of penetrating oil up behind the door handle whilst opening and closing it, would have cured the problem without having had the hassle of dismantling everything.. what is it they say, ' hindsight is a wonderful thing'!
I hope this experience may help someone else who encounters the same problem.
Cheers Ivan