“9(a) The agreement between the Tug owner and the Hirer is and shall be governed by English law and the Tug owner and the Hirer hereby accept, subject to the proviso contained in sub-clause (b) hereof, the exclusive jurisdiction of the English Courts… (b) No suit shall be brought in any jurisdiction other than that provided in sub-clause (a) hereof save that either the Tug owner or the Hirer shall have the option to bring proceedings in rem to obtain the arrest of or other similar remedy against any vessel or property owned by the other party hereto in any jurisdiction where such vessel or property may be found.”