It looks amazing, with the letter box, the door-knocker, the bells and... without the knob? I just checked with "The Study in Pink" and apparently there isn't a knob in the door. Weird. That's why John always uses the knocker...

If I hadn't known that this is supposed to look like that I would have been worried of it being broken ;)
I never noticed it! You often say I know more Sherlock details than you but you're ahead of me with this one :)