Claimed for a lost engagement, now recovered. What now? (United Kingdom)

Hi everyone, hope okay to post here…

In January my Fiancé lost her engagement ring at an amusement centre with trampolines, fair rides etc. On the way out she noticed her ring was no longer there, devastated. We reported it to the company straight away, logged it with the police, went back the following day looked for hours (we knew we wouldn’t find it but we felt like we had to try) and we made a claim with the insurance company on our home insurance who were very helpful and paid out for the ring at the insured amount (annoyingly I had to get it retrospectively valued for a like for like by by the jeweller -at the request of the insurer- and it was much, much more than I paid for it 6 years ago (cost of materials etc.)).

Basically, with the money they paid out we decided to take a little family holiday and get a cheap ring as my Fiancé wanted the memories for us and our two daughters. Fair enough.

This morning, my 6 year old wanted to do drawing for her unwell grandmother and found my fiancés ring in our 2.5 year olds pencil case… I’m delighted and my fiance is too but where do we stand with telling the insurance company? Since all this has happened, our policy expired 2 months ago with the insurer that paid out and we are with a new insurer, do I need to notify the old insurer? Do I need to refund the money that has now been spent (approx 2.5k). Can I insure the ring again?

Any thoughts are welcome!

TLDR; Fiancé lost her ring at amusement centre, claimed on home insurance, insurance company sent a cheque for insured sum. Spent the payout money on a holiday and a cheaper ring. The ring that was declared lost was found by our daughter in our younger daughter’s pencil case. What do I do from him and what are my liabilities and obligations? Can I insure that ring which was lost (now found) again?