Any help much appreciated here.
Oven has been working fine, and then all of a sudden not.
To ignite you have to turn the 'oven' knob, then hold another button in whilst clicking (a third button!) the igniter. A pilot flame then lights, you let go of the button you're holding in and we're cooking.
HOWEVER, what happens now is that when you let go off the button the small flame disappears and will not stay on. We've tried holding the button in for up to ten minutes, but as soon as we let go, the flame disappears.