My toilet needs to be flushed usually at least twice, I am guessing because the drain pipe comes off the back of the toilet at 90 degrees instead of straight down to get to the down pipe so must be getting some back flow. Also I am guessing the cistern is one of the smaller ones.
Welcome to the Bunnings Workshop community @jchill. It's great to have you join us, and many thanks for letting us know about your toilet flushing issue.
How long have you been in the property, and has this always been the case? Apart from the slightly convoluted pipework, there could potentially be a partial blockage down the line. You could also investigate other issues by taking off the lid of the cistern. When the button is pressed, is all the water in the tank is dispensed? If not, perhaps the flush mechanism is broken and needs replacing. Whilst you are there, check to see how far up the sides of the tank the water fills. If there is room to spare, you'll likely be able to adjust your float valve to increase the volume of water held in the tank. Currently, it might be set low to conserve water.
I'm keen to hear more about the issue and find a solution.
That's an unusual arrangement for the outlet. Normally it would go down, straight out the back, or maybe to one side then straight out, so there's a couple of extra bends for it to go around, and it might be slowing the flow down.
Why is it like that? The mark on the floor suggests the toilet used to be closer to the wall. I'm guessing there used to be a skew trap toilet there, and when someone went to replace it, they found they cost a lot more, so they converted a normal one. It might be that if you get the fitting this plumber used then there would be less bends:
Or you could move the toilet forward to get rid of two bends, but it would be a long way out from the wall. It might be worth trying raising the toilet a bit to see if the extra height is enough to get it to flow better. The joint might be flexible enough to try that without having to replace all those pipe fittings.
The trouble with this sort of thing is that every option is a gamble.