Most rescues wouldn't rehome to anything less than 5ftx2ftx2ft with an attached run.
Rescue is the best way to go, as is getting two buns instead of one.
Have you got room for a bunny shed instead? Or house bunny(s)?
If you post pictures of both, maybe someone can help you adjust it/ think of how it can be changed
I still think the avery is an option...
I'm not sure my mom would let me or the neighbours because they are right moners. I would love to take there rabbits as they have a stupid 5ft by 2ft cage for 2 rabbits that never even get access tovthe outside Its such ashame