I have booted into Workbench and opened the shell and types "mount PC0". Initially it told me that "PC0" couldn't be found
: was missing, that's why it complained.
mount PC0:
when I insert a DD floppy formatted on my PC it won't recognise it and comes up with DF0:
That is normal. You should see both PC0 and DF0 however. When amiga floppy is in the drive you should see PC0:

and the amiga volume. When MSDOS floppy is in the drive you should see DF0:

and the msdos volume.