Drak

Can anyone recommend a supplier for a NOX Sensor 1 and after replacement is there any reconfiguration required?

Good information, thanks. Although I get the error message I've noticed that I still get an Adblue countdown so it is injecting Adblue which is obviously a good sign.

How many miles do folk get between clearing fault code and the engine management light coming back on?

I have this exact problem. There is a "SCR Nox Catalyst Efficiency Below Threshold Bank 1 catayst 1" fault which appears approximately every 150 miles after reset. I took the car to a local VAG specialist garage and the ran an adlue test plan. They replaced the adblue injector. After 150 miles EML came on again so went back to garage and they put the old injector back in (refunded money) and said they thought it was a software issue and to take it to the Skoda dealership. Skoda dealer says that the software is already up-to-date and there are no updates available. They ran exhaustive tests on the adblue system which were all perfect (adblue quality, pressure, volume emitted at injector, cleanliness of pipes). Outcome was they suggested the catalytic convertor was failing and should be replaced. I don't see any smoke from exhaust, the exhaust is clean at outlet, there is no loss of power or drop in mpg, no reduction in acceleration or rotten egg smell. After seeing the above posts with this same problem I am hoping that it is just a software issue and will continue driving and resetting EML in the mean time.