HD Bay 1, underneath the track pad, has no screws or caddy.
HD Bay 2, at the rear of the laptop, has a cuddy with 2 screws that support the HD.
Both bays have there own clear insulation plastic that's screwed on to your HD.
*edit* Ah yes, just had another look and spotted some plastic screwed in that was removable. Sorry, for my initial blonde moment and not being able to spot this first time round.
The hard-drive screwed into this and is now secure so thanks for the input. Wonder if the drive will get a little warm, as there doesn't appear to be much ventilation in the second bay?