Lighting - splotches / caustic problems

Hi

I've followed the advice in the splotches pdf to try and get rid of the problems you can see in the attached image around the ceiling raft and on the column. I've set indirect caustics to none and visible to indirect rays un-checked for the ceiling material. I'm rendering using interior best but still having problems. Any suggestions? I've attached the dgn.

Microstation 08.11.09.459 Windows 8 pro

ground3d-Base.dgn