We need to start thinking of a route. Can you please give your ideas into what places and shops you want to see?
Just my 2cents:
I´d stick to the Fitzrovia side of town. That way we could cover place like Lewis Leathers, Rivet&Hide and Clutch by foot. Miriads of places to have a drink/grab some pub food around too.
The East end is arguably more picturesque but somewhat far off, and I can´t think of "need-to-see" places other than maybe Son of a Stag.
Others (locals) will be more qualified to give advice, and I don´t know if I can even make it, so pls. feel free to disregard the above entirely.