Roddy, I expect you are having a similar issue to I am having.
If I load the latest package I only get one result from the list. I found that if I load a package from December 2019 it will create a list of new materials based on the excel file above.
But all the fill materials and colours are default empty. I suspect it is associated with the error. I get about loading the \Dynamo Revit\2.6\packages\Genius Loci\bin\itextsharp.dll
Failed to load library … Dynamo\Dynamo Revit\2.6\packages\Genius Loci\bin\itextsharp.dll
At least I can create the materials. I can probably assign colours and patterns separately.
If you use the latest package you do not get the error but it only creates 1 item form the list (the first) but it does colour it in.
One other think you need to close the material pallet in Revit for it to create the materials. It does not seem to over write existing materials either. This is probably a good thing in retrospect.
If I find a work around I will upload.