What is this King George V jubilee (1935) item with holes all round side

It is approx the size of a medal or similar to an old half-crown coin. It is thin copper-coloured metal. On front is a (royal?) coat of arms. On back:Outer circle, going around: THEIR MAJESTIES JING GEORGE V AND QUEEN MARY; INNER CIRCLE: ASCENDED THE THRONE . in centre in straight rows: 8th May 1910 . .. JUBILEE . ... 1935. It is like 2 thin metal buttons, back to back, but separated by a strip of the same metal with 15 equally-spaced oval holes cut through that strip (see 2nd photo of 3 above). It was in my mother's (born 1926) jewellery box for as long a I can remember with other odds and end like out of circulation coins. Those holes look as though they serve some purpose. Could it be some sort of large jewellery finding for joining together strings of beads?

 

Have you tried blowing through the open holes?
Whistle, tuner?

 

I second blowing on it - I suspect it was some sort of noisemaker.

 

The holes are equally and closely spaced so inspired tho- it was I do NOT think this is a mini tambourine.
I have tried blowing on it BUT it is totally hollow - just like two domed coins back-to back and there are 15 holes ALL THE WAY ROUND. If there was just one or two holes I could possibly be persuaded. However a noise maker seems a bit disrespectful for a royal jubilee commemorative object.

 

Could it be a lid out of something?