I have had so much trouble with PN since november culminating in 7kbps speed in the evenings. The upshot is that I am migrating to an LLU provider on 12th. How are my referral payments dealt with after my migration - that is assuming that any of my referrals stay as they too are suffering with speed issues.
You'll still get them, I certainly do. You may have to update some details after you've moved to ensure they go to your bank account. I think it's done when a certain value is reached, so not every month, but you can check in the Member Centre.