Don't go cutting it off, I'll pop you an Allen key in the post, cos you'll need to refit the knob when it's modded.
I wouldn't worry too much about the tarp being fire retardent, it'll be rolled up and out of the way. An old cotton hanky (or a bit cut off a shirt) will do. Cut it to size, give it a good pasting of PVA glue and roll it up - the glue helps stop any "fraying".
I'll put some tiny black tie-wraps in with the Allen key