I use gridreferencefinder.com to get OS coordinates - it gives Postcodes & lat/long and also links the point to Google maps and Bing.

I find your ST 57750 73935 to be outside 4 Melrose Place. On Streetview, No 7 can be seen above the door and No3 is identified on the bins. I can't see the paving flags on any of these - they're all hidden by cars.