I'm the opposite of knowledgeable when it comes to plumbing however I have done a fair amount of searching through forums to find an answer to my problem and unfortunately still have questions.
To make it easier, I have taken a picture of the pipes as well as the actual waste hose behind my machine.
The hose from the machine sits in what I believe is called the standpipe on the left and goes approximately half a foot down.
I have taken apart the p bend (or u bend - still don't know the difference) and confirmed that there is no blockage.
I have run a snake down and around all the pipes with no issues and also used some soda crystals just incase but water flows through the pipes easily.
What I believe is the issue is that the output from the machine is producing water faster than it can travel through the pipes which are 40mm in diameter.
I believe that if I removed the p bend and just replaced it with a 90° corner, it would work fine but obviously it's there for a reason and particularly with the pipes only a 6 feet from the drain, I'm very reluctant to do that.
One more thing to point out is that on the right hand side, there is a pipe which I have capped off. I was wondering if that trapped air could be preventing the water flowing down as quickly and if I need to find some kind of air valve which may allow air out?
As it stands, I have just put the waste hose into the sink next to the machine and that has let me at least use it for now.