It's been quite a while since I landed at LHR and had enough time to use the lounges.

I'm arriving @ 10am on Wednesday flying in F and I have 3 hours until my flight to EDI. I'd like to grab a shower when I arrive at London.

Looking at the BA website, I'm not completely clear which lounges are open to me and which amenities are available where. As I understand, being an F passenger I have access to the Concorde room, the arrivals lounge and the Galleries lounge? Where do I want to go for a shower, and would I need to book anything in advance or just show up?

And is it the CCR that serves the English breakfast?

Thanks!