cabin bags

So I'm heading back to Grenoble tomorrow for the first time in almost 2 years. I'm going to have to carry all of my belongings in my 55x40x20cm cabin bag (£50 to add a bag on 2 flights, I tell you!!!) which will mean wearing a week's worth of clothes during the journey. I need room in the bag for taking nice Scottish things over and (more importantly) for bringing nice French things back! Anyone know if you can take cheese in cabin luggage on a plane?