Grail CF SL7 - frozen seat post clamp bolt

Hi all

Looking for suggestions regarding a frozen seat post clamp bolt. I have tried penetrating fluid, tapping the bolt, twisting both ways and have snapped about four T25 bits in the process.

I am based in Australia and the official store / workshop is about 1.5hrs from where I live, so I am reaching out to this community to see if anyone has solutions before making the journey out there.

Yes I used carbon paste yes I torqued to correct spec using canyon torque wrench. I discovered this after getting a proper torque wrench and wanting to give everything a once over - that was weeks ago.