@SebasFP 

Afaik, QBO UK version only focuses on supporting financial institutions located within the UK. If you want to manage a SGD bank account, consider opening a Wise account to integrate with QBO. They are partnering with DBS to operate in Singapore. Then you will be able to transfer your balance easily between your SGD account and your existing account (UOB).

https://wise.prf.hn/l/64dl92k