There are 2 Shellard families in Sulgrave in 1841 but neither has a Joseph. They are:
William 40 Ag. Lab., Joyce 40, Zalek 12, Karenhappe 10, Ezra 8, Louihannah 5, Zerriah 1.
George 45 Ag. Lab., Hannah 51, Ann 25, Charlotte 18, John 15, Elizabeth 13, Jane 10, Robert 80 Ag. Lab.
All above born Northamptonshire
If you come up with any other possible towns/villages in the county I will gladly look them up for you.
Pam