I have had dreadful bunny bonding problems with Herbie & Sugar. They got on well to begin with, but it went wrong after 2 weeks. I was all set to return Sugar to the rescue, but couldn't bring myself to hand her back until I had given her another chance. I'm doing it very slowly now - buns living semi-together, both in the same room with one in a pen and the other free range and each evening I swap them over. Most evenings I have to together in a neutral space and I am seeing progress and even getting some grooming. If the bonding session starts to deteriorate, then I call it a day and take them back to their room and try again the following day, so that there's no fighting and resulting bad feeling between them.
I'm getting good progress with this slower method and I'm glad that I gave it another chance. Whichever bun is free range tends to choose to lie next to the bun in the pen. I often find them flopped out side by side with only the mesh dividing them. This might not work for everybun, but it certainly looks to be going in the right direction for my furry rascals.
Bunny screaming is dreadful, Herbie was screaming when Sugar bit him and he was still screaming with fright when I had him in my arms. It is very upsetting, so I know how you are feeling.
Good luck with whatever you decide to do and I hope you find a little girlfriend for Beau soon.
