Theme: Well, it’s fairly obvious this time. Name of a film spread out between 11-down and 40-down with its lead actor (and a quite famous one at that!) in 17-across. The “setting of 11-/40-Down” isn’t a place. And the award it received (64-across) is what you might expect for one of the all-time epic films. Don’t get misled by the answer to Meriadoc the Magnificent, even if 17-across would have made a great lead actor.
Niña, Pinta, and Santa Maria: Think generically rather than specific type.

Gather, with difficulty: Don’t be frightened!

Sicilian city: Very similar to the volcano, but not the same

Techs may have long ones: Which is why you get to hear so much wonderful music on your telephone!

Hot spot: Think -> in a house or chalet

Petrol measures: Remember, british clue, British answer