Change the sensor 1st and see if that sorts it. Did mine the other day, 10 min job and it sorted it, sensor was about £10 from euro car parts.. Apparently it is a fairly common thing to fail. Search the forum and you will find explanations of how to do it. You will need a couple of deep sockets but I can't remember the sizes I'm afraid. Its very easy tho.
If that doesn't solve it then it will be low oil pressure, could be a number of things, but check the sensor 1st.
Sorry just noticed you have a 1.2, I assume the same applies but I am not sure where the sensor is located on a 1.2.