Storad night stroage heater model number?

Hello
I have two storad night storage heaters in a flat without any model numbers on. The reason that I would like to know is the control knobs are missing and I was hoping that there might be a way of finding out.
They are at least 10 years old, both 40" long, and stand 28" from floor approx (4" is the feet). There is a grill where the heat comes through at the top, but looking at some models on the web they all look similar. I would be grateful if anyone might know.
Many thanks for your time.