if you notice on top of the GIRO form there's a mailing address. This might save you time from queueing at the branch.
If you are mailing in you might want to send a copy of your IC too. OCBC and Standard Chartered both took a copy of my IC when submitting Giro.
Giro by mail is so easy with postage pre-paid.
The "lousy" organisactions do not write back at all to acknowledge, thereby keeping you in suspense if the Giro application has been successful.
The "better" organisations will write back in 1-2wks' time, acknowledging that they have received the application and will be processing it in 4-6 wks.
The "even better" organisations will write back in 4-6wks' time, advising the Giro has been set up.
And no, a copy of IC was not required in personal mail applications to some 16 different Billing Organisations.