On and off, I have been having a orange EPC light on the dash, took it to Audi for diagnosis, they are saying it is a turbo actuator sticking, and turbo will need replacing at over £2K, anyone else fixed this another way. Or any ideas 

Had a similar issue on the Skoda VRS. You can purchase a separate genuine actuator at a fraction of the cost. I think mine was in the region of £150 or less.

 

You can also test it by taking the vacuum hose off (at the N75 valve end) and sucking on it. Stick your tongue on the end and see if it holds the vacuum. If not, it's goosed.

Check internet on how to test it for further info.

Here's an example but check and get the correct one. You may even be able to see the part number on the one on your car.

https://www.ebay.co.uk/itm/GENUINE-VW-AUDI-SEAT-SKODA-2-0Tdi-TURBO-WASTEGATE-ACTUATOR-REPAIR-KIT-03L198716A/191828163664?hash=item2ca9d97c50:g:9gkAAOSwAuNW6X5y