i think i've actually been at this pub/bar.
We ended up at a pub on the edge of a shithole of an estate, and once inside we were confronted by notices that stated: "no unauthorised drug dealing". Absolute shithole but good craic.
a fair few of the pubs don't let opposition fans in on match day. the ones closest in Shep Bush (The goose in the Green and possibly the defectors weld) and near the ground (Springbok) in particular.
there's a Walkabout, O'Neils nearby which would probably let opposition fans in