Hiya
small arguments and 'boxing' is usually acceptable, and there will probably be a lot of squeaking too, but ideally, this should calm down within a couple of days as they start to accept each other.
If they have actually wounded each other, or if there is any sign of blood, you should split them up and try again once everything has healed again.
Other signs of one being bullied is one getting much thinner than the other, once (or both) being very stressed out and looking very greasy and ragged. If they have made completely separate beds and do everything separately, then it sounds like they are not getting on, which will stress them out, and there is no point in them living together like that. The will also avoid each other whenever they come into contact.
Watch them carefully and look out for the signs - if they are getting on, you will notice them grooming each other, eating and sleeping together etc.
Good Luck,
Tammy x