sorry but I could not stop 😂 at this

"That's why businesses have stocktake sales. It means they can claim the costs in the current tax year"

yes, you sure can, but you also have the income from those sales so basically the profit goes up and so is the tax

that's not why business have these

only way these would help with tax is if you sell the stock in June and get paid in July, but then all you do is moving the tax into next year