If it's your mum's place and maybe hasn't had the attention of an RGI for a few years! And she has dementia it would be prudent to get an RGI in, to give the whole gas supply a health check anyway! Pressure test at the meter and not just a disconnect of the cooker!
Many thanks everyone, unknown to me my new neighbour is Gas Safe plumber! Gas pressure test check at the meter indicate a very tiny leakage somewhere. Disconnect the bayonet socket, re-test the gas meter and it's now okay, my mother and only just said, the gas hob always been a problem!!!! All gas pipework checked and tested. I've got her electric 2 plate electric portable hob and a combi microwave
