"On July 14, the fleet of Cruise and Marine Voyages was seized by the British government" is incorrect. As I understand it, they have never been "seized" by the Government. Five of CMV's ships (ASTORIA, ASTOR, COLUMBUS and VASCO DA GAMA) in the UK were detained under port state control procedures due to deficiencies (mainly to do with crew welfare issues - late wage payments and expired contracts, widespread situations during Covid-19) - MAGELLAN was also inspected but not detained. This was about a month ago and we do not know at present whether those deficiencies have been rectified or whether the MCA has released any of the five affected ships, but CMV have indicated that much had been resolved.
That is quite different to the closure of the CMV companies. So far as I can tell, the ownership of the ships themselves is quite separate from the UK companies, owned by individual companies run from Global Cruise Lines, Athens, and chartered to CMV. So it remains to be seen what will happen to them (each owner will of course no longer be receiving any charter hire from CMV, so must also be compromised.