HF_DATASETS_CACHE variable in Windows
Agh - I'm a muppet. No quote marks are needed.
set HF_DATASETS_CACHE = C:\Datasets
works as intended.
I can't seem to use a custom Cache directory in Windows. I have tried:

set HF_DATASETS_CACHE = "C:\Datasets"
set HF_DATASETS_CACHE = "C:/Datasets"
set HF_DATASETS_CACHE = "C:\\Datasets"
set HF_DATASETS_CACHE = "r'C:\Datasets'"
set HF_DATASETS_CACHE = "\Datasets"
set HF_DATASETS_CACHE = "/Datasets"

In each instance I get the "[WinError 123] The filename, directory name, or volume label syntax is incorrect" error when attempting to load a dataset