Found today around 2pm Sistema pack of 7 rectangular containers for bargain price of £6.00, there was about 15 left. Instore at Tesco Long Eaton only (as far as I know). These were situated with other reduced stuff at the end of an aisle. These are £16.98 on Amazon.
Sistema pack of 7 Klip It Accents various size rectangular containers - £6 @ Tesco instore