Our boiler has started making a noise on start up and when it kicks in and out engineer says it’s an ignition coil bracket and nothing to worry about but it sometimes gets worse and it went on for few seconds todays (5) like it was stuck and then freed itself and might have been coincidence but the light flickered in house. Attached a video any ideas before I start calling people and the dreaded it might be this etc and getting into a whole world of paying out for maybes thank you