Why did the Dardanelles begin without a full joint force?

Did Churchill settle for a naval attack because the army was not candid about the forces available for the Dardanelles?

Only partly; even a fully agreed joint operation still faced the practical problem of moving a large force and all its support into the theater.

The answer accepts part of the premise but adds a material constraint. A joint assault required moving a large army and the equipment needed to sustain it, not merely securing political agreement to release troops. The navy-only opening therefore cannot be explained solely by deception or personality. A strategically sound combined plan can still fail to materialize when lift, support, and deployment capacity are unavailable at the required time.