Just a note for anyone else, don't expect any new apps on the ATV 3 or earlier. This may still be for sale, but it is effectively an AirPlay device now which can still play Netflix or Now TV natively.
Apple's focus will be on the new platform which has a different OS (tvOS) and an app store.
The new Apple TV 4 platform is likely to eventually have all of the UK catch-up apps (I predict within 6 months), but none of these will arrive on the earlier devices.