What van insurance do I need to work as a courier?

I am thinking of starting up as courier, what insurance will I need and what would it cost roughly?

Why are there so few long wheelbase standard height vans on the market?

I am about to buy a van for self-employed courier work. After looking into different types of vehicle, I have decided on a Transit Custom L2H1. I like the Transit Custom for it's comfort and accessories...

What's the best van to use for courier work?

Can you advise me what van would serve me better as a courier and what would be the best way to finance it?