Helo David,
I am not familiar with the details of your fridge, but it sounds as as though the flame recognition system may have been compromised.
It may just need the Spark cable to be reconected to the electronic igniter, or the ignitor itself may have developed a fault.
In either case, if you can expose electronic ignitor without having to remove the fridge, you may be able to rectify the connection or possibly replace the unit.
Before working on the ignitor ensure that all power is disconected.
If you cannot expose the ignitor and you need to remove the fridge, then that involves breaking a gas joint then you must refer the work to a competent person who knows the gas regulations.
