Probably but that depends on a few things.
Z-wave devices run on different frequencies that vary by region, zigbee devices should work regardless of region.
If it’s generally easier/cheaper for you to order from retailers in the UK, then yeah go ahead. If you use any z-wave devices you’ll have to ensure you’re buying the ones that run on the correct z-wave frequency for the hub you bought.
This may or may not be a big deal, but some countries may consider a radio device that’s operating on an unapproved frequency to be illegal.
Like if one were to use a US hub in the UK, it’s z-wave radio is on 908MHz, but 868MHz is the approved z-wave frequency in the UK and EU.
Whether it’s realistic that someone could actually be caught violating such a law with the very low power radios in the ST hub, or what the consequences might be, is anyone’s guess. But I put that out there in case you want to look into how that applies to Singapore.
The only thing I know about the Singaporean legal system is from that incident in the 1990s when an American juvenile delinquent was convicted and sentenced to be caned for spray painting graffiti in a public space, or some such offense.