Is there a way of turning off the grid alignment rotation for parts of a survey when using the CS setting? My survey is of a cave (Upper Flood) in the UK using cs OSGB (or EPSG:27700). Some sections have been copied in from a paper survey that is already aligned to Grid North, while other sections are new surveys where I have manually specified declination to Grid North. When turning on the cs setting, I've noticed that the cave is rotated, because Therion has assumed that my survey is aligned to magnetic North.

1) change all my declination settings to be True North rather than Grid North. In this case Therion will apply the final rotation to Grid North.

Howevver, I'd prefer not to have to edit all the source files and it still leaves the problem with the old paper survey that I traced. Is there something I can do within Therion to turn off the rotation to Grid North when using the cs setting?