Top Oven Ignition Is Hit And Miss When It Comes To Staying Lit!

It can take several attempts to maintain a flame, could stay lit for several minutes and then go out of it's own accord. Many a meal has been ruined due to the fact that it was thought cooking was in progress only to find vegetables cooked on the hob etc and ready for dishing up when the meat in top oven hasn't begun to cook. Cakes have been ruined and the last straw was when my Xmas cake sank after only managing to get warm before the flame went out. The top oven just cannot be trusted, it is infuriating to say the least. I had a 2 year guarantee only just expired, during which time I had a service engineer out twice to correct this fault. Apparently I needed to keep the ignition switch held down for longer (oh really!) This most certainly is not the cause of the problem. There is even a smell of gas from the top oven on occasion when the flame has died. This was a brand new cooker installed in my newly refurbished kitchen in June 2013. From reviews, I am not the only person who has had this problem. I am an experienced cook, cooking family meals for over 40 years I am beginning to regret disposing of my cast iron Cannon cooker!!!!