Can I get transiotions lens blue colour? High street opticians say no such colour available. But one web site sells this option

No you cannot. As far as I know there is only grey and brown. What website sells that option?

This website sells various colour transition lenses including blue
Cheap Prescription and Designer Glasses

Well, look at that. It's obviously a specialty item, and I'm not entirely sure they even sell that in America, but I assume from the site that you are in Europe somewhere. I would inquire with the website for questions on their transitions. But that's kind of cool. I don't see a practical use for that color, but it could be kind of interesting as a sunglass.

Yes it caters to US customers. As I am in UK I visited their UK web site. I am not sure whether it is genuinely blue transition glass - becomes light blue in cloudy days and becomes more blue as sun light becomes stronger. Once bought it is a trouble to get money back if it is just a tint.

Tints don't change color. They have a return policy on their site. It's not a glass lens, it's a high index lens. I understand that it caters to US customers, I'm saying that I don't think that they sell that lens IN America. UV light is what activates the transition of the lens.

The company I work for use to sell color photchromic lenses in blue, teal, purple. They were very popular with the younger adults. Then we stopped carrying them. I've been trying to find them too.