Is the hold of a large commercial airliner considered a confined space?
Depends who you ask. If it's EU working regulations, then it's a yes. But they're not the authority. If you ask fire inspectors, the answer is also yes - but, then again, they're not the authority either. If you ask EASA they'll say 'not a clue, it's working or fire regulations'. And they
are the authority.
In the end, I wouldn't be surprised to find an ICAO sanctioned exemption somewhere, as a result of airline lobbying.