Smeg oven and grill not working

[Barbara & Paul]

Three weeks ago the oven functions dial put up a bit of resistance when I came to use it. I applied a little pressure and it turned and everything continued as normal. A couple of days later the grill stopped working and then yesterday the oven stopped working too.
So now no oven or grill. The functions dial turns all the way round both clockwise and anti. I'm not sure that it used to do this. The fan still operates.
I'm wondering whether it's the functions dial that is broken although this does bring the fan on, or the grill and oven elements. Any suggestions please?