Where to get last-minute tickets?

What is the place in London to get last minute tickets, for the same day or the next? I'm off to London in a week. I've already booked ahead for 5 shows, leaving any others up to last minute. Depending on how I feel and prices.

I remember getting tickets in a kiosk on Charing Cross Road where they offered cheap-ish last minute tickets for just about any show. (And I picked Wicked then because it was cheap, went in blind. It happend to be my gateway drug). But that was back in 2016, that place might not be around 9 years later, are there still physical places like that, or a spot online?

Also are discounted last minute tickets still a thing? I was in Hamburg a year ago, and had to pay full price with literally less than 10 minutes before curtain.