Peter,
Just had another thought.
Are you actually hearing a spark when you press the ignitor button.
The RMSxxx0 series of fridges (the zero on the end denoting manual energy selection and manual spark ignition) tend to have manual ignition the eventual spark being produced by a battery normally hidden behind the ignitor button.
If you are not hearing a spark it could be something as simple as a flat ignitor battery.
If this is the case, slight thumb pressure on the button while turning anti clockwise, wherein both the button and surrounding bezel will pop out exposing the battery.
If you are hearing a spark then it is back to the gas jet which is a KZ45.
Search Google for dometic kz45 jet
