So just as an update if anyone is interested:
After day 1 : , the turbo is finally out after wrestling with multiple heat shields with bolts hidden in inaccessible locations and an oil drain line that was impossible to reach.
we managed to not shear any bolts, however a few nuts were rounded off.
I think we found the source of the rattling noise, one of the down pipe studs was missing all of its thread and had no nut, the gasket in that area of the flange showed signs of gas escape.
So day 2 will be installation of replacement turbo and with the lessons learned from day 1 it should go much smoother!