You need a plumbing outlet rather than Mitre 10. Go to your local Mastertrade and ask for a 'tank fitting' - in the States its called a bulkhead. Hansens make tank fittings and there are other brands around as well. Mastertrade stocks Hansens though. I found that Mico and Plumbing World (at least where I am) didn't carry much in the way of PVC fittings.
I used 25mm fittings and the tank fitting and the elbow was just under 9cm from the glass. The fittings for 40mm will be bigger but you should be able to trim some off the elbow but that still won't get you the 5-6cm you are looking for. I don't know of a shorter way to do it.
For drilling the tank I went to Super Auto Cheap and bought a $20-$30 rotary tool with accessories that included a diamond bit. I took the tank outside, put it on the ground, ran the garden hose on it with one hand and drilled with the other. Minutes later I had a hole. No practicing. Maybe I was stupid and just lucky but I had a hole and a rotary tool that has proved really useful for other stuff as well.