Most Australian bank account numbers are 8 digits long. However, Westpac is only 6 digits long. If Bridge doesn't appear to accept your Westpac account number just add '00' to the start.
Eg. Your account number is 123 123, when entering it into Bridge, make it 00 123 123.
This is a common scenario for anyone with a Westpac account number.
If you have any questions on this, give us a bell on 1300 550 711.