UPDATE - just tried the substance loader plugin within cinema 4d, and then converting the native c4d material it makes into an octane material. This does not work as it keep the substance bespoke nodes, which crashes Octane. I though I could at least replace these nodes with matching image textures, but still get less then desirable results in quality, and a lack of the nice metallic / finish as per the examples in the links above from Jonathan.
I realise he uses Marmoset (I think) but was hoping for better results than what I am getting...disappointment