DFS4190 | Technical Guidance: How are losses treated?
From HM Revenue & Customs · Duty Free Spirits Guidance
The trader must record:
losses in storage;
accidental losses in processes;
investigations into the losses, including any management decisions taken; and
report more serious losses and deficiencies.
You should agree with the trader a level at which a loss should be reported. Obviously, a large loss for one company will be negligible for another.