Offer to the BBC 1956

A letter received by the BBC from an elderly spinster in Croydon reads:
"One thing you've never had on the wireless is twelve cats all simultaneously
and in unison singing for their supper.
I can provide the item.
It is fun to listen and to distinguish the various voices.
I suppose a microphone could be in the room with them?"

The letter adds,"I have not had a wireless for years - I had to give it up but I am wondering if the cat's voices could buy me a new set.

It would be a bright little interlude on a programme."