Two different wires associated with the Fairey Swordfish

How was 'bra wire' used on a Fairey Swordfish?

It could improvise a repair to structural bracing; the frequently mentioned torpedo wire was a separate device used to control water entry.

The question conflates two separate pieces of wire. The Swordfish's biplane structure used tension bracing, and crews could improvise a repair with strong wire taken from an underwired garment. The wire more often discussed in torpedo attacks served a different purpose: it helped make the weapon enter the sea in the intended belly-down attitude. One belongs to emergency airframe maintenance and the other to weapon release. Separating them avoids turning a colorful repair anecdote into an incorrect account of torpedo operation.