Rod,
Given that D1 is some distance from the runway (but the nearest holding point) I think that an instruction to line up would be given.
No dispute that only the tower would use take-off, but departure is a commonly used term. Probably the more correct readback would be "G-CD line up and take-off immediately".
G
[This message has been edited by Genghis the Engineer (edited 20 April 2001).]