What is the expectation from Data Holders when filling the current and available balance fields at the top level of ResponseBankingAccountsbalanceById for a Travel Money Card?
Should the DH populate the top level balance fields in this case with the default currency and value on the account e.g. if the default currency is AUD, then the amount in the AUD purse should be used to populate those fields (including when the AUD amount is $0), regardless of the amounts that exist in other purses.
That is correct. The value used for the balance should be represented as a purse entry as well.