Thank you for your comments, Daisy! We look forward to seeing any photos you can supply of the area.
In addition to the locations near you, there was also a significant Pettit presence at Margate, Kent, though I believe this is some distance away from you. At the St John Churchyard, Margate, Kent there are supposed to be several Pettits entombed and a placard commemorating displayed there their benevolent work in the community. The remnants of Dent De Lion castle are there as well which was, for a time, held by the Pettit family. I am told that the area surrounding the old castle gate is currently being excavated for some sort of housing development.
Best of luck researching your grandmother's Pettit family!