Disconnect has cooker - bayonet flex connection

no you can disconnect it yourself if any one says you can not and quotes all sorts of rules tell them to report you nothing will come of it.

Calm water plumbing is incorrect. A bayonet is a perfectly acceptable means of capping a supply to the cooker. You may disconnect yourself to clean behind the cooker, but a permanent disconnection must be done by a gas safe engineer. For the guidance of the gas companies who commented.... Guidance Note 65 to regulation 6(3) of GSIUR states:  “When an appliance is disconnected and open-ended pipework is left, the pipework should always be left sealed with an appropriate fitting. A self-sealing coupling, e.g. on a cooker connection, does not need to be capped-off, except where there is a significant risk of interference (such as by a child). However, it should be checked that any disconnected coupling is not leaking gas (see paragraph 68), and any wall- mounted connector has been installed in the downward mounted position to prevent dirt or grit getting into the self-closing seal.”

Please see other similar question I have answered: https://www.mybuilder.com/questions/v/42273/do-i-need-a-gas-engineer-to-disconnect-a-gas-hob

Hi Steve The Gas Safety(Installation and Use) Regulations 1998, Regulation 2(1) allow the disconnection of a cooker via a self sealing bayonet fitting by a person that is not Gas Safe Registered. This must only be a temporary disconnection for example, the purpose of moving the cooker for cleaning purposes. A permanent disconnection such as yours would require the removal of the bayonet fitting and capping off by a qualified Gas Safe Registered engineer. Regards Roy