After years of unforgivingly stabbing the piezo igniter in a vain hope to get the fridge to light it eventually gave up the ghost and stopped working., when you pushed the button in on occasion it would have resistance and emit a spark but mostly it just pushed in with no resistance or click.
Thankfully the part that was broken is readily available online from a number of places, the best price I got was 26 quid with free delivery.
This is what the broken one looks like

This is easy the new one looks like, pretty much identical

The part lives at the top of the fridge and the only way you can get to it is to pull the fridge out.

For our fridge I had to take off the facia at the top where where it says Dometic and all the controls are, two screws sets the panel free

All told it took me about 30 minutes to replace the part, put the fridge back in and find that it still didn’t light. Took the whole fridge out and checked where the burner jet is, I moved the other end of the Piezo that generates the spark closer to the jet and hey presto, it starts every time, finally…..