Thanks
lhrworker.
I hope you won't mind, but I took the liberty of checking this with YouFirst, and they said (of my final inbound leg, shorthaul ex-LHR):
You have access to all lounges including Concorde as you have same day connection in First with one guest.
The only lounge you cant take a guest in to is the arrive Lounges, I hope this helps.
All quite confusing! I'll take a print-out of their email I suppose...