Your file has a name long 252 characters. When WinSCP is downloading the file it adds a temporary suffix ".filepart", with which the filename length exceeds system limit.
Disable the transfer using a temporary name to workaround the problem:
Thanks for getting back to me Martin.
Would disabling the setting in the UI also affect scripts or would I have to add specific syntax to my scripts?
I only say this because I use scripts for everything and not the UI.