Hong Kong is more the issue than Singapore, but in both cases the matter would go to court. The branches are part of the total. Assets in Brussels must get shipped to HongKong if the lawsuit loses.
In fact, since it is all electronic, it would be instantaneous. And Euroclear values its business prospects in Asia.
It’s very much like what happened in Cyprus during the Greek crisis. Russian assets at Cypriot branches of British banks were at risk, but they were branches. When Cyprus announced on Friday afternoon that there would be a bail-in of the banks (funded by depositors) on Monday morning, Russian business people moved their assets from the Cypriot branches to the London branches, and then back to Moscow on Tuesday.
They had been the targets, but their money escaped.
It was this single event that started the ball rolling towards Bitcoin’s international aspect. Government confiscation is not possible in the blockchain.
Of course governments can confiscate blockchain: they just have to get the owner and hold a pistol to his head. Or his kid's.