Hello, I hope I can offer you some assistance.
Does the central locking work? If so can you unlock the front doors using the lock in the driver's door.
Let me know and I'll reply as soon as I'm able to.
as the door lock barrel is worn you need to fit a new door lock to enable the central locking to work through this lock, once you turn the key to the unlock position twice with the key the rear door will unlock.
Make sure fuse 78 is OK to enable the locking to work.
To open the doors now means shorting the wiring to the door to operate the central locking. At connector 2 of the fuse box pin 8 (yellow/violet) is 12 volts to unlock the rear door, when 12 volts is sent down this wire pin 24 (grey/brown) needs to be an earth, this will release the rear door as long as the wiring isn't damaged inside the rear door.
As I said at the beginning a new lock barrel will enable you to release the side and rear doors as they should.
Let me know if I can assist further and I'll reply as soon as I'm able to.
What fuse box you're talking about, since I can't open the bonnet so the engine fuse box is out of question..
I looked through the manual and found the fuse 78 you're talking about and checked it myself this afternoon, fuse seems to be in good shape.
thanks for the replies so far.