Is this engine bay cavity accessible?

[hoobahole]

I've dropped a bolt into the square cavity to the left of the engine mount in the attached photo.
It hasn't dropped out and I can't see where it would fall through, if at all.
I've removed the charcoal/vapour canister - nothing.
Removed wheel arch liners - nothing.
Removed the two long oblong access covers in the subframe (behind wheel) - nothing.
Any suggestions?
My extendable magnet doesn't bend...it snaps (d'oh!)
I'm about to try and shove a hoover pipe in there.

 

[Dan@SJM]

Yeh. Support the engine with a jack and remove the mount

 

[hoobahole]

Yeh. Support the engine with a jack and remove the mount

I thought that might be the case.
Thankfully the hoover got it out.