I just come across your video,thanks alot,,,ive got exactly the same problem wirh our 2017elddis with the same rooflight,such a poor design,i took the rooflight out an resealed it as i thought it was that but then i realised the roof was sagging so much,i think im gonna try an tackle the job the same as you done Thanks again for the video Cheers Dave

We have exactly the same issue with our Elddis not leaking but water pools on the top exactly like yours I have covered the joints with butyl tape as a precaution but the the roof is extremely weak in the centre.

Take it that's a lunar same problem with our alaria in process of rejecting caravan dealer won't repair it under warranty saying it's a design fault. Good video 👍