Thank you Lockister,
This post was extremely helpful. I purchased my Z3 with no A/C Tensioner Pulley and the bracket bolt socket snapped off just like yours. Everything looked so tight I would not have attempted it without removing the refrigeration lines from the compressor had your post not shown it to be possible. New bracket in now all ready to go although I did have to machine a very slight chamfer (took about 1.5 mm of material off the head of the top compressor mounting screw at a 45 degree chamfer with a bench grinder) to clear the refrigerant line compressor connector.
Would now like to torg\que the A/C Belt tensioner pulley mounting bolt to a precise Engineering Specification so as not to snap the bolt socket and having to repeat the whole exercise. Anyone know the exact torque spec for that particular bolt?
That aside tanks again for your excellent post.