How can i fix a leak from my shower enclosure?

We had a shower enclosure made last year. To did this our builder made a stud wall which, when combined with 2 walls in the corner of our bathroom made 3 sides of the enclosure. All three sides were lined with marine plywood and then a waterproof membrane.

We had a majestic door fitted.

Water escapes from the front bottom corner near the door. It has made the paint in the stud wall blister and the floorbaords swell.

We have called in Majestic who could not identify the reasons.

Any ideas?