G'day Crabbing
Yes, Raymond and the team at Universal Seletar are absolutely brilliant. They can handle you whether you are using Seletar or Changi.
As for Hong Kong, yes you are stuck with Hkbac. As said above, they will charge you for looking at them. Beware of asking them to do something for you via a 3rd party, they will slug you with a 16% admin fee, ie I you need a new bulb for your nav light, they will contact the maintainers for you, the maintainers will then sell you the bulb directly, but then your HKBAC bill will have a 16% charge reference the bulbs cost on it.
Basically just expect your lav service, water service, parking and anything else to be far more expensive than the world standard. And if they offer to do something for you, it will not be a favour, you WILL be charged.
And you will have to be very anal with you paperwork.
Cheers