I'm resurrecting this topic because I also have a problem with my Vanette GG7000.
I seem to have a similar problem with my oven as froggy, in that I can't alter the temperature of the oven. What's more, I can't turn it on or off by the knob. I have to interrupt the flow by using the stopcock. Thankfully, I have 2 supply lines: one to the stove top which can remain permanently open as all knobs work as they should; but whereas the grill works fine, turning the supply on opens up the gas in the oven, so to make toast, I have to make sure I light the oven as well. A bit of a waste of gas if I have nothing else to cook. When I'm finished, I have to close the stop cock to extinguish the oven.
I don't understand what a thermocouple is, but I think the problem is with the bit of wizardry immediately behind the oven knob, which I assume is the thermostat. Has anyone experience problems like this before? Can anyone confirm what I'm thinking?
It seems Vanette are out of business, and the oven must be nearly 20 years old, so gGiven the cost of a new thermostat, I'm tempted just to buy a new oven.