Single Rabbits

My rabbit lives on her own, but she has access to a very very large grassy area which has chickens in during the day. I also have four guinea pigs which have access to the same area. The guinea pigs vary from one to about four years old. They all have access to a large internal area in a barn, the guinea pigs are supposed to be in one and the bun in the other. The problem is that they all swap around and I never know where I will find them. The guineapigs always put themselves to bed in their internal accommodation, the rabbit often prefers to stay outside, although she may very well come inside later when I am not around.

The rabbit has loads of places to investigate, she has made three burrows, two underneath the chicken houses and one underneath a pile of bricks. She seems to enjoy being with the guinea pigs and chickens. She does eat the mixed corn when I throw it to the chickens and always comes running when she sees me. I catch her up every few days and groom her and check her over. She has hay, veggies, rabbit food when she wants as its always in her internal accommodation. Of course, she also always has access to the grass.

The question is, bearing in mind that I remember reading on here that rabbits shouldnt mix with chickens nor guinea pigs, should I be worried. I would add that I have had lots of rabbits that have all lived the same way. Leonora is quite feisty with me and I have a feeling she would probably not be particularly welcoming to another rabbit. She has been neutered. I feel she is a very happy, active rabbit that spends her days investigating her home, she often has a silly turn and rushes round and round jumping in the air, and does not seem to be lonely, but am I wrong?

Thanks for input The problem would come if the new rabbit did not get on with the guinea pigs as it would be unfair to restrict Leonora to a smaller area, now she has got used to such a large play ground.

Luna was a feisty scamp before but she loves Thistle to bits and has actually calmed down since they were paired up! I think if u can then it would be a good and nice idea, making her life just that little bit more brilliant (even tho it sounds amazing already!)