there is within the itv hub player if you select Settings on the top row then from a second row that appears About there is a option to Reset your ITV Hub Settings and that will require you to sign into your ITV account again
not sure if that will resolve your issue but could be worth trying
The only problem with Hub+ via Amazon is their inability to keep it updated. You'll find some shows only have one or two episodes uploaded and the rest of the series is missing, or some programmes never get uploaded at all. I ditched it for that reason.