Here the draught cover has been taken off for checking

Here the draught cover has been taken off for checking and repair. The gas blue flame can be seen alight after the repair.

Should the burner assembly require removing, due to a fault condition. Then the Two screws securing the assembly are removed and the assembly pulled out. Remember to turn off the gas before carrying out this proceedure.
Below can be seen the burner module removed for exchanging or repair:

This particular module would flame up, but go out after 10secs. With the panel lamps indicating Green & Red. i.e 'No Gas' fault, as the flame had been alight then I concluded the module was faulty.

Burner module removed ready for exchanging or repair