The clock is almost finished, but already there are requests to do more with it. The DHT has asked whether it could go in the hall, and chime like the real clock does.
I've not spoken to the children yet about this as I want to make sure it's possible - but I'm thinking a Raspberry Pi Zero, a speaker, the computer clock and some audio files might help it to chime.
Watch this space!
Update: after testing with an older Raspberry Pi Model (version2) and a set of headphones, I'm pleased to say that the idea works. A short program in the terminal window of the Raspberry Pi, a change to the cron settings to run the program automatically and that's it!