Just a repeat of my last post on the old thread....
Welcome astar - always good to see a fellow maxi fan!
Shame about the Wolseley. Have had a think and a quick google. Couple of suggestions below, but I am not precious, so tell me if I am miles off target!
Sofitel St James Choice of Brassierie Roux for 'proper' lunch. Rose Lounge for Afternoon tea, or the bar that also does light lunches. I have stayed here a couple of times and it is nice.
Wine Bar at Fortnum and Mason Does food and has either 1 45 or 2 45 availability]]
also The Parlour at Fortnum and Mason. Has a table at 2pm
Gallery Only table at 1245.
I am sure there are loads others - just going on the little I know about the general area!