I'm not sure, you might want to see if there is an email address and drop them a line.
I have been browseing my googla search to see if I could find anything to work for you, but so far I see covers for the 5 LNB , but no pictures ot all kinds of them for the 18" dishes.
You also might want to grab one of these that DO , do the teams and email them about the Slimline dishes to see if they now handle them, no telling how often these sites get updated.
I am also looking for a dish heater ( LNB) , one that is NOT controlled by a temp sensor. I want to be able to plug it in when needed and unplug otherwise. I am afraid that the ones with temp sensors will be on when there is no bad weather in sight.
I sound on for the 5 LNB but it has the sensor and it is $ 130 I find that to be quite steep.
Jimbo