Forgive me I can’t link to it directly because I’m on my phone, there’s a new Only Connect app out featuring both Connecting Walls and Missing Vowels. It’s made by solid Welsh outfit Cube Interactive and it’s £1.49 on Apple’s app store, I haven’t checked Android yet. Journalism, there.
I’ve also not yet played it myself, although all in all I think it’s a pretty safe gamble.
Edit: it is indeed on Android.
As far as I can tell all of the Missing Vowels in the app are from old episodes, although I’ve only played six or so, so this may be wrong. The walls, however, seem new.
Disappointingly, when the timer ends, the music doesn’t crescendo off as it does in the original app.