How to repair faulty Indesit WM12X?

Hi, the selector knob on my Indesit WM12X keeps rotating around within several minutes of a new wash being started.
I have stopped the cycle and have selected another, and in the past it has fully completed without any further complication. However now, I am finding that the clothes are still damp despite being spun several times.
I have checked the filter and this is clear. Also, I have noticed that the LED light flashes 7 times in between pauses. Is it possible to easily fix this myself or would it be more advisable to get a professional out?

Elle
March 2015