bigstripeytiger I am happy to answer your questions. First I want to say I am going to give you the advice that is recommended and for the best of the rabbit but I dont mean it as a criticism in any way at all - the thing is no one tells you a lot of this stuff til you chance upon the right person so you couldnt be expected to know all of it.
Meusli food for rabbits is not good because they are selective eaters. It is like giving a child chocolate, sweets & broccoli. They are likely to not fill up on broccoli. Not only are the "sweet" bits not as healthy but they also do not do the required job of wearing your rabbits teeth down. This is essential as their teeth will get totally out of control, cause them great pain, sometimes death even. The reason uniform pellets are so healthy is that all the nutrients from a complete diet are mashed together and put into a mould so that when your rabbit eats it they cant help but eat the healthy stuff. And they are much harder so the rabbit gets to chew down their teeth. Food is the most important thing to get right for a rabbit and sadly the thing most often got wrong.
Also a rabbit has to have about 80% of its diet hay. A rabbit wont eat hay if they are given too much of the other types of food. Hay wears the teeth down and gives them the fibre they need to keep their systems going. Rabbits have really horrible digestive tracts, a little blockage can hurt them a lot.
If you are going to change your rabbits diet for the better best to do it gradually, mix some pellets (SS or Excel) with the meusli gradually getting rid of the meusli altogether over a week. Your rabbit is likely love the pellets so much you wont have any problems. Then make sure you give fresh hay every day. A rabbit wont eat stale hay. You can use straw for bedding and hay for food that is a good way of monitoring how much hay they eat and both are really cheap.
It is a very rare rabbit that wont be happier in a pair or group. Rabbits dont like living alone as a rule. They are prey and social animals and they actually fall in love! Its true - you get a male/female (neutered) pair and they will adore each other, grooming, sleeping, cuddling, chasing.
If you are able to get another I would it is really for the best. But your boy will need to have been neutered first, I cant stress enough how much you dont want babies. They will cost you a fortune to take care of and also add to the huge problem of rabbits in rescues. There are hundreds of thousands of them. I can tell you the rescue nearest you if you let me know what part of the country you are in. I may even know of lady bunnies looking for love near you. Your boy will need to be neutered for 3-4 weeks before you bring a girl to him because he will still be fertile in that time. A good rabbit rescue can help you with bonding the pair but they will make it a requirement that one or both is neutered. Rescues are swamped with unwanted rabbits, especially now because people are handing them back because they cant afford them. We see some really sad cases and there are so many lovely bunnies who would adore a great home.
Your female really should be spayed too, even if your boy is done, because as I said earlier it will add years to her life and also very importantly make her nicer to be around. Horny female rabbits are neurotic and a real PITA. They get much more mellow and happy once you have relieved them from the need to get humped every 5 mins. You are very likely to find though if you go through a good rescue a female will have already been done. Some rescues do this as a matter of course before they release a rabbit to a new family.
As you can see I really do know a stupid amount of rabbit stuff - sadly not just rabbits also cats, degus, blah blah blah. I wanted to be a veterinary nurse but I've been in the animal care world a long time. If you have any other questions at all or want to join the forum I belong to you can email me senatorvass at gmail dot com - it is a really friendly bunch. This particular forum is great because no one jumps down your throat or anything. Some animal forums are quite literally rabid & I think it puts people off a lot.
Hope thats helped a little & there's more where that came from