For the record I have also had this problem with both front doors on my Lag II
I think I am right in saying that it's not the clip failure that causes the problem but the wear and tear on the cables. They fray and then the system becomes damaged. The white cips on the Laguna seem to be designed specifically to break out of their soft mountings if the system is under too much tension thus avoiding an accident of wires snapping under very high load.
I paid £60 for the regulator from a local french car salvager but got a windscreen repair place to fit it ( just in case I dropped the glass ).