Thanks for your messages.
Just to update, he is still doing okay, but obviously not to his full extent. I am thinking about a few things at the moment and deciding on the best course of action for the future. It is just that I am 16 years old now (off to Uni in less than 2 years), and to be honest, haven't been spending the time with them recently anyway (due to college work and other things), I don't think it would be fair to bring another rabbit in, as it isn't really an ideal home. I am thinking about rehoming him to someone who currently has a bunny they want to bond with him. I obviously need to think about it, but I am in Hampshire if you may know someone who is interested.
I hope you understand.
Dan