OK thanks. I should have realised that. I'll blame it on a stuffed up head cold :-)
Raw is only possible in the usual A,S,P,M modes. The rest, & there are many, only use jpegs.
So for jpegs the question would be whether to do it in-camera or in Photoshop>Filter>Noise>Reduction (I think it looks like the same engine as the ACR noise reduction)