Re: Gas Cooker and Chains..
Never heard of this but I pay for my boiler to be serviced, not my cooker, although I suppose it should cover all gas appliances for safety's sake.
Mindst, that's a tale in itself!
A couple of years ago I smelled gas and, although I always keep my window "locked open" to four inches, it came over very strongly, so I got a plumber in who discovered that I had a ruptured gas pipe to my cooker. No wonder gas was costing me a fortune, but I'd been lucky because I'd kept a window open, but nothing was mentioned about it being chained to the wall then.
A boiler service doesn't usually cover other gas appliances though.