There should be a feature in Kashflow to record opening and closing stock levels, for an accounting period, e.g. a year, a month, or whatever is required. The P & L report is not accurate if account is not taken of increases and decreases in stock levels, as this has a direct effect on Gross Profit percentages, and therefore net profits. When an accountant produces year end P & L , stock levels are usually included, therefore why is this not possible to include on Kashflow, as a tool for producing more accurate reports. Without this information the report is not an accurate reflection of the trading position.
I raised this some time ago - it is because Kashflow operates on the cash basis only - ie purchases are recorded in full when items are paid, rather than stock adjustments being made at year end / year start.
You need to ensure that when reporting your accounts to HMRC, you tick to saay that you are using the cash basis