Dangerous roof light - partial solution

 you need to have to log in ..... 

I have a similar roof light in the end bathroom of my 2013 Coachman however there is a vertical bolt/latch on the slots for the more open position.

If it was any other forum I'd be able post a picture ..... 😐

Thanks, thought it was me going doolaly. . he made the video and can't see it.

I saw the spring too 

I think I see what you are referring to, but it is nothing to do with the problem of the roof light unlatching itself.

Look at the first photo, which is the video at 1.15 mins. If I understand you correctly, you are referring to the spring indicated by the red arrow. This spring partly balances the opening mechanism to make it easier for the user to open the light. It is not part of the latching mechanism.

The latching is done by a peg at the each end of the opening bar, which latches into a shaped groove, at the point indicated by the green arrow. The second photo shows the grooves that the end pins locate in (not photo is mirror image of video)

You are quite right about the latest models. Here is a photo of the large roof light on a 2019 Bailey, with a lock on both opening positions. The fact that the design has been modified shows that they have had problems, even though it has been denied. (The caravan dealer had told me that the new models were not different, so they must be trying to cover up too.)

Importantly, this is not just a Bailey issue, as may makes of caravan and motorhome have fitted the faulty roof-light design, (as witnessed by the problem some of members have reported on this post.)

the spring is assisting the bar. push the window up and the spring will pull the bar to the vertical slot so when you let go of the window the bar will drop down in to the vertical part of the slot just like if the wind got to it. try taking spring off and pushing the window again and bar will stay near the end. If the spring was attached to other end of said window bracket it will assist in holding the bar at the correct end. hope you get my explanation.

A neat solution. Note my other post showing how the manufacturers have at last fixed the fault in their latest product.

I'd spotted this problem on the same rooflight fitted to our previous Elddis Crapvan 2014 model - I just squeezed 50mm of garden hose into each  main channel under the selected vent position - tight enough to prevent release but easy enough to reposition as required.

Crude but cheap (a bit like the caravan!)