Orange Lock out button?

Sorry I put this request in the Answer box not the Question Box…Doh!

Anyway here it is again in case….

Hi very useful thank you regarding me finding the burner lockout but unfortunately the orange reset button goes in but then buzzes and within 10 seconds it clicks back to orange. Boiler won't fire up even with 1.5 bar on dial and a full tank of oil. The aerator outside is only 2 cm high so is it starved of oil maybe? it has been smelling of oil for a few months while it was working ok? Thank you to whoever you are out there ;-)