Resetting Ferroli 80E Combi Boiler?

Hope someone may be able to help. The red lock out light is on on our Ferroli 80 E Combi Boiler due to our gas being shut off. The reset knob (inside & outside) has snapped off due to becoming brittle.

My question is this : Can we somehow reset the boiler without this knob?
and
Can we buy the correct parts? (I've seen the knob available but not the attaching piece of plastic and spring inside the lower control panel).

Hope this all makes sense, thanks in advance. :-(