I've had 3 Series IIA's and a Series 3 but that does not look vaguely familiar. It appears to be some sort of lifting bracket considering the thickness of the steel (?). Maybe some sort of aftermarket or fabricated item.
I'd look for two holes that match up to the bolts on the bracket, or, just throw it in the spare parts box and someday it may become apparent what it's for. One thing I have learned, these old Land-Rovers, due to their utilitarian nature, have been modified and modified over the years to perform specialized functions. It is extremely rare to find one in a totally un-modified state today.
Bob
'69 Series IIA
'74 Series 3, 109 pick-up truck
+ various other LBC's