The Lacie petit series drives seem impossible to get in to. After getting into mine the wrong way, the right way became obvious. I'll show you it.
Using a fingernail or other tool, pry out the indicator light (shown on the far left here). You will find that it is actually a small, soft plastic plug
Insert the handle end of the 2mm allen key into the hole left in step one. You may have to wiggle it around until it fits into the concealed bolt. Unscrew it counter-clockwize 18 turns. If you do it more than that, a piece will fall out inside the case, but it is no problem to screw it back on.
The internals will now easily slide out of either end of the case.
You can now see what we have done. Unscrewing the screw, which you can see on the left, has decompressed the black rubber bar, so it no longer presses on the case, allowing it to slide freely.
(Note: that drive is not the correct hard drive: that one was in the freezer, chilling off to see if I can get data off it.)
To remove the drive, peel off the thin rubber strap shown here first. This rubber strap has knobs on it that fit into the screw holes in the drive.
Then pry off the plastic moulding from the left-hand end, and slide the drive out