Thanks Art. Hopefully you'll never need to do this one! One additional notation I should have mentioned that's important...

When we installed the new sensor and tested it by starting the car, it wouldn't fire which left us feeling queezy considering the ordeal of removing the old one. Using the LED light, we noticed the new CPS wasn't fully seated at the bore end despite being bolted in and torqued. We had a rough time removing the new sensor as it was really wedged in the bracket. Here we go again I thought. After wiggling back and forth and carefully twisting we finally got it out. Should it really have to be this tight?? We filed and then used emery cloth to shave down the outer circumference of the stub. Dry fit it a few more times till it slipped into the bore as it should and then applied some silicone grease for good measure in case it needed to come out again. Fired right up afterwards! What a relief. There was maybe a 1/16" gap so the tolerance is obviously critical here. Anyway glad it ended well and praying it fixes my friend's no start issue in damp weather. He's happy regardless. At least we'll know it isn't the CPS now.