Konstantin and I generated a signal in the Messhütte and sent it to the ESR. 
There, we used a 44m BNC cable that was sufficently long to reach all detectors. 
Our signal was connected instead of the PMT/PD. Hence, it was a roundtrip measurement.
In the Messhütte we checked the delay between the generated signal.

PD North 1460(1)ns
PD South 1455(1)ns
Particle North 1239(1)ns
Particle South 1179(1)ns
UV North 1322(1)ns
UV Middle 1322(1)ns
UV South 1321(1)ns
Cu 1322(1)ns

We also checked the time delay of our cable to the detectors by measuring the reflection of the unterminated cable. 
Function generator to detector: 1520(5)/2 ns
Function generator to scope: 5.1(5) ns
Total: 765(3) ns