Your comment gives only 2 options.
There is at least a 3rd option, and quite possibly more.
Whilst the bases have, I believe, their own different collective agreements, would you agree it’s conceivable that CX may, instead of the 2 doomsday scenarios mentioned, actually offer the bases the chance to align themselves with the HK CoS18 contract, by the individual associations, such as Europe, Canada USA and those troublesome antipodeans, putting a vote to their respective membership to accept Cos18CanadaStyle for example.
It may we’ll be that the incentive for the membership to accept, would be the threat of CX saying something along the lines of “The current basing structure, with regard to leave, medical, pay structure and remuneration is now out of alignment with HK, and to ensure stability and employment for all going forward, the only way basings are viable is for the respective based association membership to vote to adopt the new CoS18 contract (by say 31 March 2021 as an example), or CX will enact the provisions of base closure”
Sam Ting Wong - do tell what the offer to the UK or Europe folk was. Could it have been a 3 months notice to accept CoS18 ora continuation of the 80%, or pay concessions in excess of 20%. Do tell, don’t leave us all hanging.