I had a look at Britbox yesterday and some articles about the content. BBC and ITV are both continuing with their catch up services. ITV will move stuff to Britbox after 30 days, next year was mentioned. BBC will leave their catch up as it is and programmes will be moved to Britbox after a year. Next year Ch 4 and Ch 5 will be adding some content to Britbox.
Taking all this into account and as I don’t use Amazon Prime very much, I’ll probably try Britbox for a bit after Christmas and see how it goes. I expect Britbox will be added to Amazon firestick, if it’s not there already.
After the failure of Samsung to update BBC app, I suspect most of my TV will be watched through the firestick.