I've heard the rumours of the 2nd A330 however yet to see this come to fruition but not only that i think the longer it is left the harder Jet2 will find to fill it. So they'll probably stick to the 1 A330 out of MAN. Who knows!?
As for the order i don't believe a single word. Until i see this confirmed by Jet2 themselves i won't believe that they will order the A330. I believe that they have areas where they can grow - BFS with 737-800, BHX, STN along with the older bases. New destinations in Greece, Italy and new city break destinations along with new base or two to in the West Country/Wales.