But if your looking at buying a van for £2200 it's going to be fairly old and have quite a few miles on it, which means it will probably need more repairs than a newer van, which because you own it you will have to pay for and that will have to come out your £480 take home, so while it's off the road for repair you'll be losing money, then you'll have the repair bill, might only be £50 for changing a wheel bearing, but could just as easily be a gearbox or engine costing £500+ to repair and however many days off waiting for the garage to fit it in.
Ideally you'd want a lwb high roof sprinter, much more reliable, more comfortable, not too bad on fuel and they ride a lot better than a boxer, new transits are sh!t, they go through starter motors, clutch's, flywheels and fuel pumps like they are going out of fashion.
You need to think, is the possibility of earning £480 per week worth the risk of having the time off and cost of repairs and work going slack, £350 per week guaranteed is better than £480 profit 1 week then £100 profit the next, not knowing what is coming in from 1 week to the next, then the possibility of big bills.
If you do decide to go for it good luck and I hope it works out for you.