Replacement for Indesit Click&Clean IS5G1PMSS/UK 50cm Gas Cooker

Hi, just purchased one of these cookers: indesit.co.uk/pro…ers but am really disappointed by the heat produced from the oven. Previously I had a cheap Montpellier model which had a really good, even heat for cooking. This new Indesit model feels like it's giving off 30-40% less heat!! I need to replace it. Any suggestions? Cheers.