Hello to you too, Is it a pub type bottle or fire extinguisher.Im quite sure somebody more knowledgeable regarding question will be along shortly.
I used to get mine re-tested and re-filled at a fire extinguisher supplier. They should have the necessary facilities.
Might be worth looking them up in Yellow Pages or your favourite search engine.
Blazetechfire's phone number puts them in the Thetford area, AFS Fire protection are in Wymondham, for example, but there are others.
any idea of cost of having it retested?
its a 10ltr pub co2 bottle