radiator air vent

Hey, So I have this kind of Tower Rad installed: https://victoriaplum.com/product/the-heating-co-santa-fe-traditional-radiator-952-x-659 As per the pictures attached it doesn't use the standard 1/2” BSP valve size, what is it using? I am guessing it is a 1/4? Cheers

I replaced the air vent and blanking plug at either end of one of my radiators by following the advice in the thread at this link: https://www.diynot.com/diy/threads/radiator-leak.360889/ I used an ordinary spanner. I would like to be able to replace the air vent on another of my radiators...