I was about to go out and buy a second hand replacement for £160 and thought i'll have one last go.
I removed the gas supply to the fridge at the top, released the pipework to the base and all covers, removed the ignitor and thermocouple, I then removed the actual burner and found that it contained a small aluminium cap with a tiny hole.
I removed the cap and tried to see light through the hole and couldn't. I then got a small needle and tried to feel the hole, to find that the hole was blocked. I carefully inseted the end of the needle and then re-assembled using gas plumbing paste on all joints.
I then turned on the gas and applied a liberal amount of soapy water to each joint to test it. I then lit the gas to find I had a MUCH stronger flame. I then replaced the fridge to its rightful possition and relit, I left it running for 3 hours to find that the freezer section was freezing for the first time on gas this year.
So I can now use the £160 on something else...
Tony Dane, June 2008