The bank's supplier for desktop computer hardware was Dell. If Dell could deliver it, it was ordered from Dell. There was no "choice". And yes, it was a list price, no negotiation involved.
There were plenty of competing products in the UK - I could have had a better mouse for cheaper by wandering down to PC World, down the road, and paying £10. But the corporate ordering process didn't allow me to get involved in that - all I could do was express the fact that I needed a mouse with a wheel.
If Dell could deliver it, it was ordered from Dell.
Well, there you have it. If you are Dell and you secure that exclusive deal, you get to charge high margins on certain incidental products.
Of course, as has been pointed out by olefoo, to get a deal like that Dell probably had to give up a lot of margin on other products. And throw in support contracts, and expend a lot of sales time...
There were plenty of competing products in the UK - I could have had a better mouse for cheaper by wandering down to PC World, down the road, and paying £10. But the corporate ordering process didn't allow me to get involved in that - all I could do was express the fact that I needed a mouse with a wheel.