Sorry, I had to do some further checking to get the date of that petition ... 24 Apr 1833.

I checked the 1851 census for Kitely and find only William born in 1776 in Scotland and James born 1816 in Scotland with their respective households there.

William is on lot 10 Concession 1 and James is on lot 15 Concession 1, which was possibly Robert's half lot.