I know your going in tomorrow and it should be found.
But could you tell me what is the current rate of water loss?
Do you believe it leaks whilst driving, or after you have driven for 20 minutes or more and parked it?
Does it sound like its bubbling when you stop?
Have you had a real good look and feel around the back of the block near the fire wall?
edit: It's been my personal experience when you stop a leak another is found. UNLESS all hoses are replaced.
I hope this was done during the build. Although CRD failed to do this with mine and I had 1 leak then another. So bit the bullet and did the lot.