IMHO, clamp meters aren't accurate enough for this sort of low current measurement - and are pretty expensive for DC anyway.
Short out the DVM with a piece of wire until the locking has operated, then remove the wire. A jump lead in the earth will do - and its clamp to the battery will give a convenient place to clip the DVM to. Put the other end of the jump lead to a convenient chassis earth, and next the other end of the DVM to the earth lead. Then remove the jump lead to chassis after the locks have operated.