They don't have a concierge or someone at a desk that stands there all the time, like a lot of hotels. However, you can usually find someone walking around, or possibly go in the breakfast room/restaurant to find someone and ask them. I wouldn't rely on being able to do so, though. And depending on the time of day, they might be very busy and won't have time to help you.
Keep in mind that there are apps on your phone that you can use, like Google Maps and Citymapper. And if that doesn't work, I would just ask someone on the street. Most Londoners are friendly, and if you find someone that doesn't look like they're in a hurry, they'd be more than happy to direct you.
But really, it wouldn't hurt to research stuff like this ahead of time. For example, if you know you're going to use the HoHo Bus and you know you're staying at a certain hotel, find out where the HoHo Bus stops near your hotel before your go. That way, you'll have that information ahead of time. Obviously, there are some things that you will be doing at that time, but a lot of information can be found well ahead of time.
That's why I spend so much time researching my trips, so I don't have to wait until the last minute to ask someone where something is. Not that there's anything wrong with that, but it just makes your stay a whole lot easier, and you can get to where you're going quicker if you don't have to stop and look for someone to help you.
I don't think they have pamphlets at PIs although they may have them, and I just don't remember. If they did, they would be marketing brochures for tours and sightseeing places. If you want pamphlets about London in general, you'd be better off going to one of the tourist information centers. They have a ton of information and dedicated staffers who can answer your questions. I know there's one in Victoria, which I think is where you're staying, right? https://www.visitlondon.com/traveller-information/place/470021-victoria-visitor-centre