How to open siezed back door on Peugeot 106?

Please help! I've read all posts on this subject - no luck - spent hours and hours trying to free up my back door which is jammed shut. The central locking is fine but I think the lever in the actual door which closes the door has jammed - have stripped inside of door off and tried to free all moving parts plus sprayed WD40 - about to roll the car off a cliff now - HELP! How do you access the door catch whilst the door is shut????