INIU Power Bank, Slimmest & Lightest 10000mAh Portable Charge 15W High-Speed (USB C In & Output) - £9.30 (with voucher) @ Amazon

From INIU--the SAFE Fast Charge Pro】Experience the safest charging with over 38 million global users. At INIU, we use only the highest-quality materials, so we do have the confidence to provide an industry-leading 3-year warranty.
✅【Market's Thinnest 10000mAh】The thinnest 0.5-inch body breaks the limit of 10,000mAh power banks. Lighten travel lovers’ pockets extremely, yet mighty for a whole weekend getaway.
✅【Only 5% Got USB-C IN&OUT】INIU is the only 5% of power banks got a USB-C IN&OUT port. Unlike others only recharge via USB-C port, INIU can charge all devices with your USB-C cables directly.
✅【3A High-Speed Charging】3A fast charging fuels iPhone up to 78% in just one hour. INIU's AutoFit identifies and meets your device's ideal speed, charging double than 2.1A chargers.
✅【15-Layer SAFE Charging】INIU's unique 15-Layer SmartProtect system shrugs off any unusual charging at the start. Take overheating risk and battery damage away from your devices.
✅【What You Get】INIU 10000mAh portable charger*1, 0.3M/1ft USB-A to USB-C Cable*1, travel pouch*1, user manual*1, 30 days money-back guarantee, INIU industry-leading 3-year warranty and lifetime technical support.