My plumbing experience was to have the plumbing disconnected under the sink so the counter top and new sink could be installed. I thought the service of $115 was high, but usually if there is an additional fees, it is usually rolled into the cost of repairs or labor. This company also charged 3.75 % for putting it on a credit card, which was not mentioned until I received the invoice in the mail after paying on the phone.
If your bathroom sink is slowly draining instead of holding water, your problem is super easy to fix. You likely just need to make a quick adjustment to the assembly under the sink. Pop-up drains have an arm that reaches down the drain and connects to a little rod. That rod sticks through the drain pipe and is held in place by a metal strip with holes in it. That strip, in turn, is connected to the little lever or handle you pull on to open and close the stopper. The video above from HomeAdditionPlus has an excellent look at how to make adjustments.
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license