Hi, Im currently installing my bathroom and everything was going to plan until I came to connecting up the new bath mixer tap, the two Hot & Cold flexi hoses are a funny size, I bought two 22mm isolation valves presuming that they would connect straight into these, just like the new sink tap but in 15mm, but for some reason they are a bit smaller than 22mm does anyone know what this size is??? so I can have a bath haha