Finding the place

You've been walking around London for 2 hours now, trying to find the offices where Sienna works at in MI-6. At first, you had tried looking up 1 Merlin Lane on your phone, but the internet said there's no such address listed in London. After that, you asked around for directions, hoping someone might be able to point you in the right direction, but either nobody had heard of the place, or they thought you were being a wise guy and playing a prank.

When you're tired from walking and asking for directions, you take a break at a small fish and chips eatery near Westminster Abbey. When you're done with your food, you look around to see if anyone can help you in your search. It's sort of a low-end establishment and most people are dressed casually, which makes 1 particular person sitting by himself stand out like a sore thumb. He's a middle-aged man in a 3-piece suit and a bowler hat. He has a mustache that's tidy and well-groomed, which look like a rectangular block on his upper lip. He's seated 2 tables away from you, and the table in between you 2 is unoccupied. He has just finished his meal too, and you try to get his attention to ask him if he knows where Merlin Lane is. He doesn't notice you as it seems he feels a vibration in his breast pocket and he pulls out his phone. He looks at the screen and frowns, then stands up hastily. Next, he pulls out a pocket watch tucked into the vest of his suit, glances at it, and quickly walks out of the eatery.

Intrigued, you follow him, calling after him and trying to get his attention, but he seems oblivious to you, walking briskly towards Westminster Abbey. Annoyed, you now want to give him a piece of your mind for being so rude, so you try to catch up, but he is surprisingly fast on his feet. Right before coming up to the famous abbey, he makes a sharp turn into an alley and you lose sight of him. By the time you get to the alley, which is a long, narrow path between 2 tall buildings, the man has disappeared.

That's strange, you think, because you can see all the way to the other end of the alley, which would take at least 1 minute or 2 to get to even if the man had started running, but there's no sign of him. There's no way he could have walked through the alley in the few seconds you didn't have eyes on him. Cautiously, you enter the alley, wary that the man was going to jump out of a hidden corner and ambush you, but there are no hiding places. The alley is empty, with no back doors to the buildings on either side or any way out except the 2 ends. You walk to the end and look around. It's a normal London street and you don't see the man. Not knowing what to do, you turn around and walk back to the other side of the alley, intending to go check out Westminster Abbey. Since you can't find what you were looking for, you might as well see the sights.

You keep looking left and right as you walk, still puzzled about how the man had disappeared. Near the end of the alley, there's a mural and you stop to study it. The mural depicts a typical scene in London, with streets, shops and people. You think it's kind of stupid to paint the scene of a street in an alley, and you're about to walk away, when you notice something weird. The mural is very detailed, which includes vivid images of people's faces, but what catches your eye is the street sign on one of the streets near the right edge of the painting. It's a side street named Merlin Lane.