CREATE TABLE table_52685 ("Driver" TEXT, "Constructor" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

What is the average grid for piers courage?
SELECT AVG("Grid") FROM table_52685 WHERE "Driver" = 'piers courage'
SELECT AVG("Grid") FROM "table_52685" WHERE "Driver" = 'piers courage'