Patent rights assignment

For safety and clarity, it is probably best to have assignments registered within each country that patents exist. Sometimes, when an assignment is first executed by the inventors to a company, the assignment usually covers the fact that all rights to the invention in question covers all patents, in all countries, whatever, but it is probably better to implement assignments for each one or all of the patents in each country. The most important thing in connection with assignments is to establish a clear chain of title, so you will probably need documents evidencing the creation of S-UK by S, the assignment of the patents to S-UK, and a copy of the board resolution authorizing the liquidator to distribute all of the assets of S-UK to S. This will then effectively establish a clear chain of title from S to S-UK, and back to S.

Requirements for assignment vary from country to country, and, yes, the most important thing is to establish a clear chain of title - which can become cumbersome and expensive.
Thus, for a start it should be checked whether the patent applications and patents are still alive or revivable. Again, requirements (e.g. for timely filing responses to office actions and paying renewal fees) vary from country to country. As S-UK was disolved about six ago, many of the patent assets may be in "bad shape".
So, contact a patent attorney and provide all basic details that you are aware of (applicant name, patent application number, patent numbers...)

I agree with Steven and Hanns-Juergen that it would probably be best to record the assignment separately in each country because of the different requirements in each country. For example, you mentioned that the patent assets include patent cases in Australia. In Australia, an assignment document has to be executed by both the assignor and the assignee. In some countries, only the assignor needs to execute the assignment document. It may be possible to prepare an assignment document that satisfies all these requirements. However, this would require you to invest the time and effort to determine the individual requirements in each country and prepare the consolidated assignment document and get it executed. There may also be country-specific requirements including translation, notarization and legalization of the assignment document which would further complicate matters. The easiest way forward appears to be to contact your patent attorneys in each of these countries to prepare an assignment document best suited for their practice and execute the lot at the same time.