Evap Purge Valve 1.4TSI

I Have a 1.4TSI petrol 2015 Octavia that I have owned from new. I took it for an MOT and service (non Skoda garage) . I received a call saying it had failed on emissions and mech suspected the Lambda sensor. After inspecting the fuel system he told me it now passed and said it was the solenoid in the Evap purge valve that was stuck. He cleaned it and after rechecking it now passed. I was not charged anything for that. Having never heard of this engine part I asked what it was and was told it vents fumes through a carbon filter. Any never had any warning lights to indicate the failure of this valve.

So 2 weeks later my exhaust engine light came on. The car still running as normal. I called the garage and was asked to pop in. Two days later the light went out and has not come on again. 

I went to the garage and they were busy. Short of booking it in there was not a mech on hand to assist.

My question is where is this valve. I have seen pictures of the valve and where it is sighted on various other cars but cannot identify it when looking under my bonnet or where the charcoal canister is sighted. I should add that when it failed MOT no warning light was on and so despite the warning light going off this time I'm not convinced that it hasn't got stuck again. Up to the MOT fail and after with careful driving I still get 55mph on motorway journeys taking it easy so I don't think this valve has any real effect on the performance but maybe i am wrong on that.