Its pretty straightforward really. The two tricky bits are two circlips and the lock barrel itself. The circlip you can see on the end in the last picture needs really small circlip pliers. The slightly larger one that holds the barrel in isn't so bad.
The lock barrel needs a delicate touch to take apart as the tiny springs have a habit of first getting stuck, and then escaping when you poke them, but if you're careful and methodical its not too bad. If you keep the key in the barrel it will hold all the tumblers in place until you're ready to remove them.
A new lock is £200 or so and has to be ordered from Germany using the VIN if you want to keep the same key so its well worth taking the time to fix the old one
