Roof Blind

Our new to us Warwick XL rear roof blind keeps jamming as it closes on the night blind. It seems as though there is something causing it to tighten as it finally closes and requires quite some force to close or open but when its open struggles to stay on the runner. I wondered if anyone had suffered something similar or any ideas what was causing it. Many thanks in advance

Just been to autosleeper to have our blind repaired under warranty 
Our blind kept jamming,and it turned out to be the blind itself was coming out of the runner
The remedy was to adjust the outside casing(somehow)
Works perfect now

Mine occasionally drops out of its runner and jams, but is easily put back in to place. When it’s fully open or fully closed, there isn’t much play, but I’ve just taken these two images to show how much play there is at the halfway point, where it usually drops out. 

If I take care to keep it central, it doesn’t fall out.

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Our Kingham was same as Kingham’s, when van was in Autosleepers for some work mentioned it to them, said no problem to correct, simple adjustment. Don’t know what they did but perfect now.

Many thanks everyone. Ours is like your 2nd image Kingham but is at the night blind being closed end (flyscreen retracted). I'll get the cover off and have a look when i get a chance and look at adjustment as its also allowing the card blind to come out along its length

The internal plastic bezel that finishes the look of the roof light And contains the winding handle pops off the roof. Start in one corner pop it off the fastener and work your way around until you’ve got the whole bezel removed, you can then see how crude the fixings are and adjust the blind runners. 
20 minute job rather than round trip to the dealer etc.