Most of the TV catchup services in the UK still use flash
I uninstalled Flash in the early 2010's. If a site required it, they did not get my business. Today, if I ever come across a site that requires Flash, then two possibilities come to mind: (a) the site is compromised and is trying to push fake Flash Player malware or (b) the site is obsolete.
I was very surprised to find that Comcast Xfinity (the biggest cable provider in the US) requires flash to watch their programming via a web browser.