most of us don't believe in "maintenance". It's the messy stages of growing locks that make you grow more as a person.
That being said, there are ways to make you locks look a bit neater. There's a gel from dreadlockshampoo.com that is water soluble and washes out after each wash. It even starts to break down before that, so it doesn't get stuck in your hair leaving residue. It's oil based, so it makes your locks smell nice as well. I am using it currently, to make a few of my new babies on top of my head look a bit neater for my wedding.
People have come here after doing so much damage to their hair with the thought that maintaining them would make their locks grow and form faster. But for them, there's a whole forum dedicated to recovery from thoseprocesses.
The only real maintenance you need for locks is to wash them often and separate them as needed so they don't congo into 1 giant lock.
As for jobs, I don't know what the laws are like in the UK, but in the States, we have the first amendment that protects freedom of religion. Not every one grows their locks for spiritual reasons, but for those that do, they are protected from discrimination from employers. There is probably a law similar to that in the UK. Perhaps, not worded the same way, but something to that effect.
Otherwise, people wear hats, bandannas, tams, scarfs, or just tie them back to make themselves look neater.
There's nothing you need to do to maintain locks, though. locks happen on their own, so most anything you do will just inhibit them from forming.