Anyway, a very long story short, I kind of muddle my way through to finding them as follows:
- open your file manager under "system" on the home page (scroll far right)
- click "add source"
- click "browse" on the RHS
- enter root system
- click "data"
- locate the HDD you want (it may be a series of numbers, do trial and error)
- click "OK" and rename file as you wish
Go back to home file manager and with luck your external hard drives will now be on display. Worked for me, so good luck.