Located at 56 Leadenhall Street, near Aldgate Underground station, is the experience. It looks fairly innocuous from the outside, but as soon as you step through the doors you're in another world. The themed holding area is technically "The Spirit of Man Bar", where if you arrive early, or decide afterwards, you can have moderately price food and drink, at least by London standards.
My experience was booked for 2:20pm, and you're told to arrive half an hour early, although it transpired there was no briefing as it was just to stop latecomers. So I availed myself of a pint of lager at the bar. I could still check in, and was given a colour coded wristband. I was also given a keycard for lockers, which were off to one side, so I stowed my rucksack. Every 10-15 minutes there are jets of steam from the gorgeously themed fighting machine that straddles the restaurant, and these indicate that the next group are up. There's also a light above the door to the experience which flashes the the colour of the relevant wristband. A group seemed to consist of a maximum of 12 people, and I joined a group of 10.
Once in the experience you get a briefing from one of the various masked helpers, mostly about how to wear the virtual reality equipment. As with all the other helpers and actors this is done in character from the era of HG Wells' book. I'm not going to spoil the rest of it with too much detail, but suffice to say there are then a mix of different experiences. There are several interactive performances, where you deal with a character from the story within a themed area. They or another actor/helper will then move you on to the next area. Woven within this are 4 virtual reality experiences, all bar one of these is static, in that you sit/stand and wear a VR headset. Static is not quite accurate though as a couple of them involve physical motion of the vehicle you're sat in, just to add to the excitement. One of the VR sequences is free roaming, as you wear a backpack that holds the computer which drives the virtual reality element. There is also a mini-360° cinema. For the most part it's all well done. The actors and themed areas are engaging. The virtual reality bits are clearly cutting edge, particularly the free roaming element. Fortunately I have worn a VR headset before so knew what to expect, but I did have at least one person crash into me. Protip: keep yours arms out in front of you to make sure you're not going to bump into something, or someone. In the free roaming bit I ended up on the wrong side of a wall and missed a small part of the story. In a seated section the person in front of me displayed as standing up when they should have been sitting down, which drew me out of the experience a little. One of the sequences also had an issue with the sync of the video and audio. But these were all minor niggles on what I've already mentioned is fairly cutting edge tech, and at some points it was unintentionally amusing. After the first hour or so there's a break in "The Red Weed Bar", a small themed area where you can buy a drink if you want. It was definitely a good idea to plan in the break. Then there's another half an hour of the experience, so overall it's around 2 hours.
Of course this wouldn't be Jeff Wayne's War of the Worlds without the very famous music, which accompanies pretty much everything, and is used as a cue for some of the elements.
I would rate the experience an 8/10, albeit with the skew that I'm a huge fan of the music (40 years and counting!). Overall it was really good, with just the minor technical niggles. I don't think it matters if you know the album or not, in fact it can act as an introduction to it, with a lot of added dimensions. You need to be reasonably fit to do the experience, and can't have issues with claustrophobia - the website gives a lot of detail on this. There is a slide (!), a narrow spiral staircase, and various obstacles to climb over, among other things. Currently the experience shows as ending mid-November 2019, at least you can't book tickets beyond then.