Fixed!
I spent about 2 hours today, changing the level of the machine, adjusting the angle of the shooter but nothing worked. I tried playfield at 6deg, 6.5deg, 7deg nothing. The ball continued to hit the middle targets. I even checked all the transistors for the shooter, thinking it wasn't getting enough power...
THEN....brainwave.
From watching some videos of the designers testing on whitewoods, I was manually flicking the ball from the shooter lane with my fingers, different powers, angles and still not working. This is when I thought it has to be something else. Whilst staring at the metal wall ramp from the shooter lane, I noticed an adjustment for the top end (where the ball comes out) with a screw and long bracket for it (pictured).
Moved the bracket and perfect. I searched and searched and couldn't find anywhere about this bracket so now I'm happy.
What was even better, I then cranked the playfield angle back to 6.5-7deg, glass back on then proceeded to get my highest score ever. Two super jackpots, redline mania and without cheating with secret mania either!!