Well, better be too warm than too cold in the winter
When you have the door flap zipped shut, is there still a hole so you can poke your fishing rod out of it and continue fishing?
( Theoban What of it, Fri 5 Jun 2009, 17:24, archived)

as you can see the rods stay outside of the bivvy
www2.b3ta.com/host/creative/23553/1228673004/bivvym3.jpg
( mongychops, Fri 5 Jun 2009, 17:27, archived)