What you've been sent is the radiator for the diesel variant - as opposed to what appears to be the 1.25l Zetec petrol engine in your first diagram.
You're correct in that the "main" radiator connections are the same between the two (Despite the confusing placement of the lower hose on the second diagram it is the same hose and hooks up in the same place as on the first one)
The small "extra" connection on it is an overflow pipe back to the expansion tank, in theory if you were to block it off then the radiator might "just work" - however the internals of the radiator are going to be designed on the basis that coolant should be able to flow out of that outlet. So you're going to have to be very, very confident in buttoning that up pretty tight or you'll have Fun with Coolant Leaks!*
Honestly I'd be sending it back and asking them to send you the right one.
*No actual fun included.