Ok, so this is embarrassing but at least I learnt something!
It appears the issue was with the .csv, even though I had checked it before copying it to the server, it was blank and also had the wrong column names in it, I know, weird and makes no sense!
I would have thought I was going crazy if it was not witnessed by a colleague!
So, after checking the .csv on the server, importing it and running the code, it worked!