The Shackle 14 Pro is one Oxford’s most secure D locks, with the Sold Secure rating of Pedal Cycle Diamond.
You can buy these locks from the Five Valley Cycles website. Use promo code: FIVEVALLEYEYCLES for a 10% discount: https://www.fivevalleycycles.co.uk/product-page/oxford-shackle14-pro-u-lock-260mm-x-177mm