Following links included in this answer, I noticed the IRST is located on the left side of the Eurofighter Typhoon. It seems that this asymmetrical location is common (Dassault Rafale, MIG 29,...).
Why is the location of this device chosen so that on side seems privileged? I see no reason to prefer one side over the other, there should be the same chance for a target to be located on one side or on the other.