I think it's poor planning to go past Southampton to Zeebrugge then back to Southampton and then pass Zeebrugge to Bremerhaven. Why not just go Southampton - Zeebrugge - Bremerhaven?
The GLOVIS COSMOS was always scheduled to route Southampton - Bremerhaven - Hamburg - Antwerp before heading off down to the Middle East as part of a regular RoRo route. What changed is the early arrival at Southampton and the possibility to dovetail the end of a charter and the beginning of a regular route.