DSA Laptop

I have been given a dsa laptop (option to upgrade, not yet ordered). I am only a Mac user, so need to upgrade to a max. They are charging £800 to upgrade to a MacBook Air and claiming the price to be £1198.80 (£999), my question is who are capita’s suppliers and why are they spending nearly £200 more on a laptop than the price direct from the retailer?

I feel completely ripped off, so I have requested to get it from the retailer. Slightly annoyed as I don’t want to spend £800 on a new laptop (£500 would’ve been doable), but dsa refuse to put the software I need on my current 2020 Mac, as it’s “too old”.