Figuring that by now, Greg was probably at least semi-settled in, Marcus was taking it upon himself to make sure that his cousin at least knew some of the places in Monument Alley so that he wasn't stuck in the work-home cycle that had taken over Marcus' life when he'd first come to London. He'd slept in a little later than intended on Sunday, so it wasn't until after lunch time that he managed to drag himself out of the house and towards the building where he knew Greg had moved in.
Marcus paused in the entryway at the question, leaning slightly to his left so that he could look up the stairs. "I'm looking for one of your tenants?" he answered, sounding slightly tentative about his own answer. This must be the infamous Mrs. McHavelock, and he really didn't want to make Greg's life difficult by inadvertently upsetting his landlady.
"If you could just point me in the correct direction of Gregory Goyle's flat, I will be out of your hair, ma'am," he said, holding out his hands in what was hopefully a placating manner.