"So, does anybody know if its possible in LR to automatically apply different levels of NR depending on ISO used? "
Yes it is, you can set default develop settings to any camera model and iso combination. First go into Lightroom: Preferences: and tick the Make defaults specific to camera ISO setting box, then go into the develop module and develop one image at the specific iso in the way you would want every image shot at that iso with that camera adjusted, then go to the Develop sub menu, not the module button, under Develop click the Set Default Settings, you then get a dialogue box that sounds a bit sinister but it tells you what it is creating, all images shot with that model camera and iso will, by default, get the current develop setting applied. They are of course, completely reversible.
Wow, thank you very much! This is very cool indeed
I also ticked the 'make defaults specific to camera serial number' option so I can distinguish between my camera's. I'm really happy now - still have to decide on the levels of NR I require though. Maybe I can have a peek at the default settings in DPP for each iso to get something to work from.
5D3, 5D2, Sony α6000 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: SY12 f/2, Ʃ19 & 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses.