Talking Pictures TV is launching a
Connected Red Button service on 1st September on Freeview.
Thanks to Kevin1960 on Digital Spy for the heads-up.
A look on their website and there's already a FAQ.
It's not an App as such, it's a Portal version of their current catch-up service on their website.
FAQ -->
https://www.tptvencore.co.uk/faq/red-button-faqs