Hi Col,
I have just replaced two of my large Dometic window screens, it is an issue for the design and Dometic (requested by the caravan dealer, 1 year old van) sent me replacements free of charge, which I fitted.
We have now also fitted curtains as well so we can enjoy a breeze with some privacy without the blocking effect of the blank silver screen.
With the Dometic blinds you must be careful not to brush against them as it causes the blind to be pulled out of it's track and they jam, I got away with re-tracking them for a while but they slowly got worse and became stuck.
In my opinion, not a great design and way too flimsy, although not much different from other manufacturers I have looked at. I have tried to repair the old ones as spares but the retracting mechanism refuses to work properly.
I think my next move would be to add to my curtain upgrade and put in aluminium fly screens with hinges and do away with the Dometic set-up altogether.

Col,
I should have mentioned that the dealer said to travel with the blind and flyscreen in the open position (which we had never heard of).
He says this will help the mechanism to work when at rest. I spose, we havent had an issue since we have done this so there might be something in it.....

There is an easy fix for the blinds.My motorhome suffered the same problems,hard to lift and would not retract blinds so I removed the window,laid it on the dining table and removed the roller blinds .At the end of the blind  is a bearing that has dried up lubricant in it.I cleaned the bearing and lubricated it with lithium grease and reassembled the blind and refitted the window.That was five years ago and they have worked very well since.If you don't fix the problem you risk tearing the blinds,so for half an hours work .it's well worth it............Peter

 

-- Edited by 2foot6 on Friday 8th of February 2019 09:31:21 PM