One of the things that really threw me off the scent is also the seemingly rather wide nature of the road here. The camera angle is obviously playing some tricks because this part of Shanghai Street is really no wider than any other part as you'll see in the Streetview capture below.
You can see the buildings are pretty much unchanged, but there is much less overhead signage (although I can one sign is still there in the distance) and of course there has been massive high-rise development at the far end. Look carefully and you can also see the black characters can still be discerned on the lower floor wall of the corner building (on the corner of Nanking Street).
Anyway, credit where credit is due and I've pasted Thomas' comments below so you can see where the information came from.
I might have found something. There was another Watch company captured in the foreground called 廣濟表行. I googled it and found someone posted a photo of a Rolex with invoice in discuss.com.hk showing three addresses on the invoice. Two in Kowloon ...http://www.discuss.com.hk/viewthread.php?tid=14690593&page=3
Address one reads #126 Shanghai Street and address 2 reads #224-226 Tai Po Road. I remember there was a Kowloon Watch Co. Store around the location about 20 years ago. Might have to check other older photos of the area for clues.