Just looks like an inline tap such as either end of this: https://www.toolstation.com/straight-braided-filling-loop-part-l/p83963?store=O8&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed
Thanks to your advice decided to replace the whole filling loop instead of just the valve, and just as well because the non return valve on the old one was at fault. All working good now and no leaks so far...
@BobbyBriggs started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Just looks like an inline tap such as either end of this: https://www.toolstation.com/straight-braided-filling-loop-part-l/p83963?store=O8&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed