I've not got the time to confirm, however TCX is operating B767-300 that are at least 25 years old. Also, they have a number of early A330 that are more than 20 years old. TCX major maintenance is contracted out to a third party in the middle east. Jet2 care for all their own aircraft here in the UK.
Personally I have no issue, when it comes to the age of an aircraft, all are maintained to the same highest standard.