Well for me it's been a month since I got in contact with Channel 4 on the audio issue and still nothing in response of any substance, just the same old "try resetting the Smart Hub" that's failed repeatedly to touch the problem.
Still using the Fire Stick exclusively for All 4 which is a pain but not the end of the world.
I don't think Samsung have any control over the apps however so until Channel 4's engineers pull their collective fingers out and release an update solving this problem we're all stuck.
My suggestion would be to remove all the adverts on Sausung TV's since it's them that break the functionality.
I put my TV on last night and got a message saying samsung needs to up date. after update all catchup apps are deleted and no way of re-installing them. called samsung this morning and have been told samsung are aware of the issue and there is no fix available, nor will there be. Seems Samsung have not paid anyone in the UK the app owners licence fee to install these apps and so they are being slowly uninstalled. Nor can you install any apps outwith the samsung app store. So Samsung are less than useless.