The site of this garage, is of course just a very small part of the history of the old city. Most history of that place and the area lie beneath the surface. Quite interesting excavations and the subsequent finds have given much information of the areas past, illustrating the various industries that were undertaken in the early and late medieval times. Most seem to have been located there due to the amount of water/river that was a large feature of the place. It revealed that some of the area, where the garage was, was built-up ground enabling structures to be built.
Digbeth and Deritend have so much hidden history* that is still being discovered.
* "Birmingham The Hidden History" - if you haven't got a copy, treat yourself to one.