Okay - further to my early rants about CDSE data, it aint as bad as I thought it also prompted me to properly sort out my approach to scaling/offsets which had been driving me mad! So if anyone cares for another way to download data from CDSE, with #rspatial / #gdal I made a gist:
https://gist.github.com/h-a-graham/86cd3403445cf163ce958efa2d29c621
There are still some improvements to be made for sure.
FYI @Micha_Silver