There is a misconception that brokers can get better rates than applying directly to the bank or vice versa but its incorrect with most lenders. A good example of CBA where brokers and bankers send requests to the same team and this works very well.
Other lenders have different teams - one...
Depends.
Its best to get the broker (and its part of their job) to request the pricing discount for almost all lenders except for ANZ and Westpac.
You will get a higher discount if you approach these lenders' discharge unit directly and not via the broker.