Thornes and National Bee Supplies sell a snap shut 'clean cut' valve (called the 'perfection' valve with NBS) which is meant to be drip free, I have one but have yet to try it. I think you need a metal bottling tank as it needs a robust foundation to work effectively.
https://beekeeping.co.uk/products/perfection-tap?_pos=3&_sid=7cbe742de&_ss=r
https://www.thorne.co.uk/honey-and-...-storage-and-strainers/valves?product_id=6780
https://www.thorne.co.uk/honey-and-...-storage-and-strainers/valves?product_id=9036
Castle farms sell them as well < £16 delivered.