UKH

Any tips on stopping the cup getting jammed on the bottom of my windburner? Thanks 

I think some of the earlier Windburners had a slight issue with the size of the pot cozy. If you contact Cascade Design they are very helpful, they sent a replacement cozy out for mine free of charge and in good time.

Shave one of the plastic lugs down with a very sharp Stanley Knife

Yep, shave one of the lips on the inside of cup as Andypeak said. I went through the replacement cozy options from CD and as much as they were very helpful, after the 2nd replacement I gave up and went for the DIY option.

Don't push the cup on too far either. It moves the cozy up and it all jams.

Cheers guys will trim down the lugs. Unfortunately in a fit of cup related passion I have ripped the lug off that holds the cozy on.