UKPassats

Hi folks 1.9tdi AFN. I had to change the plastic coolant flange that bolts to the side of the head as it was leaking around the join between the flange and the head. I swapped over the temperature sender from the old flange as well as the rubber washer, but the plastic push in clip broke!! I managed to get another clip from out of an Audi at a local garage breaking yard.

Since all going back together the flange has been dripping intermittently from where the coolant temperature sender goes into the flange?

Any thoughts on how to cure this please. All the plastic push in clips are the same I assume?