The issue is when I press the button to raise the spoiler manually it goes straight up as it should but then it slowly comes back down. However when the spoiler is down if I press the down button it goes up normally then comes back down slowly.
i initially thought this was the motor but I have now replaced the motor and the issue us the same.

So I've had this problem for some time now. I linked out the motor so there was no fault light but obviously the spoiler didn't go up. However I now want to sell the car and this is the only fault with the vehicle so I'd like to sell it with no issues. As rare as that is!

 

The spoiler is connected to the speed sensitive power steering. This enables it to come up at correct speed. I had an issue on my 2008 GT Speed, where the spoiler did funny things and it finally turned out to be a broken wire in the area between the boot lid and the body. The wiring connection was intermittent which was found after replacing, power steering pumps, hoses, and steering rack. Have the wiring in that area checked out. Does the car exhibit a strange feeling in the power steering at different speeds?
Ron

 

That makes sense I haven't inspected that wiring yet, power steering has been fine. Don't suppose you have a drawing of the spoiler system so I know which wire to check?

I know some people have the software for access to the drawings. There are quite a few wires in that loom

 

I just did a scan with VCDS and it's showing

01507, initialisation not successful
35-10 intermittent

 

I wish I had the wiring diagram. I am looking as well. It should be pretty apparent when you pull the coverings off. I know there is a wire that goes to the speed sensor that I was told was the bad one. It is a poor design and I happen to drive my car a lot (90K) and use the trunk every time I drive it (golf clubs).
It started out with symptoms similar to what you wrote about.
Ron

 

You may want to check if one of the switches may be stuck. I manually raised my spoiler one day and it immediately went back down. What I found was the down switch stuck slightly in the down position possibly from me spilling some coffee at one time. I couldn't figure out what was wrong so after I checked both switches i found the down switch was stuck. I worked the switch back and forth and no more problems.

 

Thanks but it isn't that because if I press the down button the spoiler goes up. So it's responding (incorrectly however) to me pressing that button.