got a job to look at above dual fuel cooker, there are some issues with the hob, 1 not igniting, and one only sometimes, one is sooting up badly and has a yellow flame, cleaned it out injector looks ok . cant take top off to inspect further because the tenant has tiled down to it!!!!! so he has to remove tiles now so I can get cooker out ect, phoned rangemaster, they didn't have a clue on part numbers so I could ordered them , can anyone point me in the right direction , im thinking some air port or something has bloked to the hob ring, any ideas? and want to order 2 new igniters . any help would be great. thanks