So, 10 minutes into a motorway journey and I suddenly get a huge power loss, won't rev over 2k and very sluggish, no smoke or vibration, all sounds normal just no power.

Off the motorway I try a few things, foot to the floor and it goes well, goes over 2k revs etc.

What could the issue be?

Thanks in advance!

Ps. Just scanned for codes and nothing.

 

are rpms bouncing at all or topping out at 2k ?

 

Check the turbo charge pipe?
This is a common issue to cause power loss.
Its the hose that goes from the EGR valve to the Intercooler.
This hose is known to crack and cause leaks, you will see oil coming out when blown.
Replacement is only from BMW - DO NOT go down the aftermarket route, you will have more issues.