I really hope there will be a positive issue... even if there wasn't any classic games since a long time, we use to go there every year, like a tradition, for trying the latest games! I've been there for the first time in 1991 or 92... I remember playing for the first time the brand new R360 and all the first 'virtual' games...is there any hope now?
I took a quick look inside the trocadero, it's just cheap shops on a short-term lease selling end-of-stock items (leather jackets, hello kitty merchandise, tourist t-shirts). It's pretty obvious they're clearing the place out to do something else in there and just renting the spaces while they wait for some longer leases to end, you can't even get to the top floors.
The Las Vegas had a couple of recent racers, 2 pinballs and some shooters but certainly nothing from the Trocadero.
There's an other arcade on Tottenham Court Road: Leisure Casino Center. They have a lot of shooters in the basement and even a couple of classics but nothing worth traveling to London for. All the latest Stern pinballs used to show up there first, when I was there they didn't even have a Rolling Stones let alone a Tron. Hell, even Brussels has Tron on location now.
So, I'd say there's little hope for the trocadero I'm afraid.
On the other hand, if you go to London, head to Forbidden Planet, they have crazy amount of video game merchandise in there these days. From pacman energy drinks to Atari joystick candy.