I've got two bonded (ML-PPP) VDSL lines coming into a property and need to increase capacity.

I'm going to check, but I'm pretty sure there is a conduit between the plinth and the ETP.

Does anyone know how do I go about getting this wire upgraded to a four pair (or more)? Do I contact the ISP or Chorus directly? 

Should I expect to be paying for this (Approx 20 metre lead-in), or is it just part of the ~$200 "new install" of the third line?

Thanks