I had a look at maybe starting to fix these. Problem is, it's not really viable. The product is at least 20 years old, parts need to be ordered. Fridge needs removing/refitting. Some times they are an easy fix, just looked at my uncles who's fridge was written off by a fridge repairer as pilot assembly broken and no longer available. I removed outside vent and found ignitor cable shorting out on back of fridge, put some insulating tape on it and all is good.
Other times you will have to order parts which could have a weeks wait to arrive, so I would have to keep the fridge until the part arrived.
It's one of those things that don't make you a lot of money unless you do loads of them. But you might catch me in a generous mood if you pm me

Time is a drug. Too much of it kills you