Good morning my name is ***** ***** will assist with your query today.
The main causes of a failed ignition (if you have checked you are getting power to the appliance), and all burners are affected s a faulty generator (which creates the spark).
A replacement generator can be found here, for around £46.
With this being a gas appliance its advisable to have a gas safe engineer install it, and then re-commission the hob once complete. If you would like me to recommend someone please provide me with your postcode.