I have been given a full set of Corolla mud flaps originally meant for a 2003 1.4 VVTi T2. Mine is exactly that model and there are 10 self tapper screws and washers in the pack too. No instructions! If I hold the flaps up to the rear of each tyre, 3 holes on the rear and two on the front (or maybe the other way round!) line up with plugged holes already holding existing trim in place. Am I meant to screw into these plugs or remove them and fix them back over the top of the flaps? Does the trim need to be removed too? If so, is it easy to remove the plugs? How are factory ones fitted? Any pointers would be much appreciated. I suppose photos would be great too.