Originally Posted by
danielbk
As far as I know the LHR T4 lounge is a "premium lounge" and does not accept O/W pax on economy, those are directed to another lounge. (Let me know if I got this wrong)
Yes OP is aware of this. Did you not read the post? It is asking about the Skyteam lounge.
Afraid I don't know the answer, but I'd advise (i) downloading the BA app for the virtual card and (ii) asking at the QR check-in counter if they provide a paper lounge invitation / voucher.