1. Take out the base of the back seat
2. Peel off the door seal from the inside and remove plastic trim fixed to the floor (held in by large trim clips)
3. Undo the 3 screws in the trim (1 in handle, 1 behind door operating handle and 1 behind ashtray) & unscrew lock pin.
4. Pull the trim off at the top by the chrome trim, then using a long thin rod, pry out as many clips as you can down each side of the door.
5. Using a large screwdriver, push the cable end out of the door operating handle.
6. Open the window, and leaning in, grab the handle in one hand and the armrest bit in the other,, and pull the trim up and out. This will be a bit stiff but it will go eventually.
6. With the trim off, disconnect the window switch and take trim out of the car (wahey!)
7. You can now take out the offending lock solenoid using a 6mm ring spanner, and unlock the door.
http://www.bmw4life.com/doorLockActuator.htm