I flew LHR-SNN rtn last week & granted EI lounge access but was asked to show my GC.
When they flew from the green mile in T1 I was refused entry to the BA lounge & told to go to the Gold Circle lounge.
I protested as it was a code share & I was GC holder but to no avail.
The EI lounge at T2 really shows up their lounge in Dublin & that Irish terminal is relatively new.