Nighthawk RAX12 speed issues

I'm having trouble getting anywhere near the speeds I could be getting?

I have recently upgraded our NBN connection to a 250/25 plan.

Doing a speed test on the  Netgear Nighthawk app I am getting results around 240mbps so I assume that is the speed I should expect????

Here is where the problem starts.......I am getting nowhere near these type of speeds.

On my PC connected by ethernet cable I am getting maximum results around 10.78mbps (download).

WiFi speed tests on laptops, mobile phones and tablets are coming in at around 90mbps.

These results are only slightly higher than when I was on the previous 100/25 plan.

I also have 2 wireless access points in the house so the WiFi signal is excellent throughout the whole house.

Do I need to reconfigure any router settings to obtain better speeds?

Do I need to reconfigure any settings on the PC?

I would assume that the ethernet connection speed should be better than the WiFi speeds...Is this correct.

Any advice would be greatly appreciated.

Thanks