Dawn, I'm sorry you are in a bad mood, but your response made me laugh. "Buggar Mum" LOL!
lilmizzsnickers - Welcome back. I am so sorry for what your family is going through, and that now you have been put in this situation. Anyway, I second digmexnow's question. What about allergy meds? I mean your mom is moving in with you right? So isn't there a way she will compromise? Plus, if she's gone so much, it's quite something for her to insist that your pets move out or be given up.
But IF there is no way around it, and your bunny must be outside, then I think you are smart to find him a friend. I do not know the wildlife of Ireland, but do you have predators - like birds of prey like owls & hawks, and/or other animals like raccoons, coyotes? One thing to note is that rabbits can be actually frightened to death, never actually being touched. So for example, if an animal just attempts to break in it could send a bunny into a deadly shock state. (so having a hidey box that will make your bunny feel safe,will be very important.) Also, you have to be sure to make the outdoor enclosure with a tight net type of chicken wire, so that no limbs can get through, or....god forbid pulled through.
OH, another note to add. You'll want to make sure to stick netting down below the ground along the borders so they can't dig out.
Also, in addition to this, maybe you could at least bring him in at night?
Keep us updated! I hope that one way or another it works out for the best.
OH, there have been some really great outdoor enclosures posted with pictures in the forum. Have you seen them? If not, I'll try and do a search.