You can live off just the maintenance loan if you wanted to, (if you find out that it is not enough, you can always ask them for the occasional top up right?)
Assuming there are 40 weeks, £4421 will give you £110+/week to spend.
Even if you spend £50-60 on food (and tbh, that is on the higher end, if you are a good cook or learn to cook this will reduce significantly), you still have £50-60 left to spend on going enough - which will also decrease depending on how much you drink. You will be left with enough for toiletries too (lots last much longer than a week).
You can ask your parents to top up if you think you will need more, but another £150 per week on top of this is quite a lot, as the others have already mentioned.
Of course, this is dependent on where you live too. In a place like Manchester, you can live quite easily off £50-70 a week.