Searches for extra heavy Z’ and W’ bosons in the leptonic Drell-Yan channel at the Large Hadron Collider (LHC) are favoured by present and future data. We focus on a common approximation used in theoretical and experimental analyses: neglecting interference between the new heavy gauge bosons and the Standard Model ones W, Z and gamma. We present the implications of adopting this approximation on the data interpretation and the extraction of exclusion limits on the W’ mass, in particular. We also address the LLP search at the new planned and proposed CERN facilities.