OP, you don't need an agent.
Admittedly I used one during covid to be able to obtain que #.
In Bangkok you will need to obtain a certificate of residence, medical, etc.
PLENTY of threads providing details of process and required docs.
Which transport office do you plan to use in Bangkok.
My Oz license on one card is car and bike
In Thailand it's two separate licenses.
If obtaining both at same time you can ask CW for one COR and photocopy.
If determined to use agent check with Fatboys or BSR bikes.
Form for COR
https://aseannow.com/applications/core/interface/file/attachment.php?id=439173