Have you bought the paint yet? If not, go to a trade place (Johnstone's very good) and get the F&B colour mixed in oil based eggshell. F&B eggshell is water based and not tough enough for kitchen units imo.
My kitchen is painted in F&B (Slipper Satin) and it doesn't have anything over the paint. Just make sure whoever does it does perfect preparation so that the paint adheres well. And make sure you cover any knots in the pine because they'll eventually bleed through.