so......
you employ a gas engineer to come and fix your broken electrode. he tells you it can be 'fixed' or replaced as a whole unit. 'fixed' is cheaper (obviously)
you go for cheaper option. gas engineer cobbles some 'drilled out repair type effort'. it works, he gets paid and goes home.
6 weeks later, you are out at work,walking the dog or whatever. wifey and kids at home tucked up in front of a lovely warm fire. something goes wrong with the fire, snuffs your whole family out!
who are you going to go for first? the knob who altered the electrode.
get in the queue, after the HSE, the police and the gastapo (gassafe)
the other option is. alter it yourself, snuff your own wife and kids out, save a few quid £100 at most, pay for their funerals (damn site more than £100) and probably get done for manslaughter after failing to prove 'competency' for messing with gas.
I'd die for my kids, i wouldnt let them die for £100.
knob