@MrsLux: If you head to Settings > Support > About This TV, then you can find the model number of the TV there. What happens when you attempt to access the catch up channels? Do you get any error messages? Have you tried accessing iplayer, itv hub etc on a different device, just in case the issue lies with their service, rather than the TV itself? As a basic troubleshooting step, try unplugging your router at the wall for around 30 seconds, then plug it back in and allow time for the reset process to complete. Once your Wi-Fi connection returns, check the apps again to see if the issue has resolved itself.
If the problem persists, please confirm your model number via the steps above, and I will look at some further troubleshooting steps for you.
