If pre-booking seats with jet2, don't waste your money.
We had checked in on line with allocated seats.
However the nice lady at check in offered to upgrade us so that the family who didn't have pre-allocated seats and were shouting could be seated together.
Perhaps i should have checked but didn't think i would be lied to so it was only when we got to the gate did i realise my son who was just 14 had been upgraded to row 1 and we were on row 26.
When i complained jet2 told me i should have paid to guarantee the seats.
Moral of the story. Don't bother. Get to check in. Start shouting. Get your own way as jet2 wont care about the customers who have followed guidelines and checked in before hand