Nationwide have sent me couple of booklets regarding the switch to Aviva. One, entitled FlexPlus Travel Insurance Provider Change, gives details of the changes in cover from the original UK Insurance policy to the new Aviva policy. In this booklet on page2 under the heading Upgrades it states: "Age: You will no longer need to buy a separate upgrade to be covered beyond your 70th birthday. You will be covered automatically."
There is no mention of an age limit under this Age heading!