@6adf5d3d I just had a look at a map and street view. From the map location, No Signboard seems like it may be right (and I would have been wrong about the walk only being 20 minutes past Bugis, more like 40, but that's a 30-plus-year-old memory). From the looks, well, you've just told us why we can't go on looks, since there's been so much tearing down and building going on. There was a noticeable outside seating area at the time, but who knows if it's still there now. 

 @7f537d63 They were in a hawker stall in race course road at the time. The location seems to match the description 

 @6adf5d3d that said, I don't think it was a hawker center but a stand-alone restaurant or stand 

 @7f537d63 They had a hawker then a stand alone near Kallang, which had far more outdoor seating. Could also be a bunch of other spots but feels like 30 years ago a foodie take on chilli crab would be that spot. 

 @6adf5d3d Ah, maybe that's it then. The distance is about right and I don't remember what twists and turns we might have taken. 

 @6adf5d3d Interestingly, that's about the time I started becoming a foodie and losing interest in 1950's Cantonese cuisine. Not sure whether the HK/Sg trip was responsible, but it's definitely around that time in my life.