Cheers Gibbo, any tips or videos to do this would be great.
I can condense some of the info in the Vega thread to give you a basic starting point that doesn't involve flashing custom BIOSes (bear in mind that I've only had my 56 a couple of days).
1. Run Wattman and choose the custom option on the slider.
2. Change voltage control to manual and set State 6 at 1080 and State 7 at 1130.
3. Increase Power Limit to +50 percent (it won't use all that, it just raises the limit).
4. Run 3DMark Timespy or the Superpositon benchmark to test for stability (both free).
5. If that's fine, bump GPU freqency by 5% and test again.
6. If that's fine, manually increase memory frequency to 950 mv and memory voltage control to 1000.
7. Test again
You can probably do more tuning and tweaking, but you don't want to push the settings so you have to increase voltage to get stability, as the idea is to lower power, lower heat, and keep thermal throttling to a minimum so that the card will use it's maximum boost and stay there. Airflow in your case is important to make this work.
For gaming, I'd probably use Chill or FRTC to limit frames to whatever is usable by your monitor. This will again keep the card cool by not doing unnecessary work, and will help keep it at it's boost speed. If you get any crashes, then you'll have to back off your GPU or memory speeds, or bump voltages to get stability. You want to keep voltages down to keep boost speeds up.
These are actually very conservative settings compared to what the guys in the Vega 64 thread are doing, so you should have no problems using these to tune up your card. If anything gets too noisy during testing, you can always drop back to the "turbo" preset on the slider. In real world games the likes off Chill and FRTC will keep noise and heat down compared to hammering things with benchmarks.