Proxy alignment will get rid of the flashing odometer, which occurs when the computer system doesn't recognise an electrical component in the car. In my case i swapped out the climate control cluster, which was faulty.
After a lot of faffing Ive solved the issue. Here are some tips as it doesn't seem that clear to me:
1. You will need a USB adaptor and a laptop running windows.
2. There are cheap ELM 327 USB knock offs on the bay that will need to be opened up and a small resistor removed in order to do the proxy alignment. It is really easy and there are threads online which document this.
2. I used Multiecuscan, all features are available for free! BUT, you guessed it not proxy, which means you will have to buy the full version for 50Euros. The free version can still be used for fault diagnosis.