I need to replace my ceramic hob which was bought in 2002. I have looked in the book that came with it and the size of the cut out in 560 x 498. I have looked at new hobs but most specify 560 x 490+2 Would this be a problem if I bought one of these hobs? I have an electrician coming to fit whatever I buy. I am an old woman who is very confused with going over and over this looking for an answer.