FIXED! I removed two little grub screws from the bonus unit disc on the top and slipped it off. Then turned the gear and sure enough it sprung back to zero but with a bit of stickiness but nothing like it was with it on. Then I played with it a bit and discovered it was binding in a certain spot and overall just sticky. I used a tiny bit of mineral spirits where the shaft contacts then worked it around. Then applied a drop of light oil and worked it some more and then it was moving really easy and would spring all the way back to zero. I put it back together and all the target bonus is now working properly.
I think it was a combination of three things, 1 it was kind of gummed up and mineral spirits and a drop of oil helped that a lot and also number 2 was the way it was being held by the grub screws it was being jammed up against the top. When I replaced the grub screws I just made sure it was tight, but not overly jammed against the top. And three, the little snow shoes where not springing down properly, as it turned they would lose contact.
Initially my problem was that it only scored the 2nd right side target bonus, this was because it was binding at the 2nd row of contacts and when it fired it would only score the once and only return back 1 set of contacts instead of going back to zero and frenchmarky mentioned that at the start which got me to realize it might have been stuck in the wrong position. HowardR asked if it was stepping 15 times at the very first reply to this thread so was right on to it but I was unable to work out how to know that.
Then currieddog mentioned the snowshoes and on inspection of those they where actually sticking up a bit and a tiny drop of oil and working them fixed that.
Then frenchmarky and paulace smashed it out of the park by exactly diagnosing it and providing the fix. Just amazes me how you guys can fix a machine on the other side of the world with the owner basically never having opened a playfield on an EM machine before.
Sounds a bit dumb but what would have helped me was video and sounds of the machine and close up of the internal parts working as they should. I'll make a few videos of it all working and throw them up on youtube in case it's useful to others.
Thanks again, I really appreciate the effort everyone made in this thread to help me. Will donate to Pinside to show my appreciation.