But they had had visual contact with the crew of the Narada, so that's what changed...
Problem is... nowhere is it mentioned that these are Romulans that attacked the Kelvin.
They only had the readings from their sensors to identify who was attacking them.
There is no problem. I'm sure the shuttles saved a lot more than that. Visual records, telemetry data, etc. In the Star Trek world since abandoning ship is an event that will be put under a court martial then you better bet the shuttles took everything they could with them. And in 25 years I'm sure someone
clued them in wouldn't you think? Especially with what was undoubtedly a major event for the federation. Word could have even traveled from Rura Penthe. Like OneBuckFilms and Hythlodeus mentioned.. things changed in this timeline.