Grace is located on the southwest corner of Dundas and Clarence at 215 Dundas.
The city is offering free 2 hour parking in the core until the end of 2020. See https://london.ca/living-london/parking for details. There is often some street parking available on Dundas and Clarence that is free after 6pm.
There is a large outdoor parking lot at King and Clarence and CitiPlaza has underground parking, accessed off King, at an evening rate of $5.
There are many places to park within walking distance to the restaurant. Visit Downtown London’s website to find a map of nearby parking locations.