- rebuilt my door lock barrel using bits from an E28. The only difference is that the stainless bezel has squarer corners than the original one (which fell off...). Once the lock is in bits you can make any lock barrel fit any key as long as you have enough bits...
-the job is a pig to do because of the access. However removing the parts isn't too bad, you can see most of what you need to do. If my memory serves me correctly you need to release all the door handle components from the door, and these will come freer when you have loosened everything enough to be able to turn the lock barrel way more than normal- the barrel actually helps to retain the door handle on a kind of bayonet. The door handle parts will be retained to the door by the actuator rod, which you don't need to remove. There is a spring clip that retains the barrel at the rear, and this is a little blighter to get back on again. You will probably drop it several times. Likewise the circlip that retains the locking actuator on the back of the barrel.
-I used PE sheeting 'builders' plastic' -they use it for membranes in floors etc. Works fine, does not degrade unlike other plastics.
cheers