Good place to rest in middle of day in London?

[Russooooo]

Hello wise ones,
I’m in London for the weekend. There’s a busy day planned and we’ll be out of the hotel from now-ish until 11pm-ish. I’m really looking forward to it, but I’m also absolutely knackered. Logistically, it won’t be possible to come back to the hotel during the day. Does anyone have any suggestions for a good place to chill out for a chunk of the day? (Hotel foyer with squishy sofas? Bookshop that lets you sit and read? Not too busy coffee places?) We’ll be central - south bank / Covent Garden etc.
Thank you!

This was the place I meant to add a link to when I said this place is good and didn't add the link!

Predictably, we ended up doing lots more walking / mooching / shopping than planned, but have now retreated to a hotel foyer. Thank you for the tips!!