I don't entirely follow the logic of the trip (but I know nothing about shipping). Tromso on the Norwegian Sea, then Klaipeda on the Baltic, now off the shore of Kent? That's very roundabout.

It's easy to come up with explanations involving bad will. There must be some legit ones too. What are they trying to achieve? Did they buy some ammonium nitrate and are trying to offload it for a buyer, but successive ports are saying no? Surely whoever paid and loaded the cargo needed some idea of where and how they will offload it.