Hey tek!
Fantastic that you have finally resolved it. I also used the red goo and maybe for 2 months the noise was gone, loved it.
It is bad now though, after about 10 mins of driving, any soft application of the brakes coming to a stop (once in a while) it will screech like crazy.
Did you grease the two pins that align the pads correctly? just run grease up and down them?
And then grease the retaining clips, which ones are these? I am guessing those wire type clips, if so which part of them?
Finally, I take it from above that you also tried rubber goo on the back of the shim so the set up is like this:
piston --> GOO --> shim1 --> GOO --> shim2 --> GOO --> back of pad