We insured a diamond ring for £8,000, then were told it was not covered

Legal & General has rejected our claim because we did not have an updated valuation certificateMy wife recently lost the diamond from her engagement ring, which must have dropped out while she was at work. We have always insured this under our home insurance. Each year the insurer has stated it will only insure it up to the value documented on an accredited valuation, regardless of what we say it’s worth. This has been the same for many years across numerous insurers’ policies. A