Currys / Dixons / PC World / The Link (old chain of phone shops) are/were all parts of Dixons Stores Group. PC World (and therefore Currys as they are now often a single building) have often had high prices for when you walk in, when compared with their web prices (where you are easily able to compare with 5+ other online suppliers).
I remember one day having a client decide they wanted a router.
4 routers in PC World. Every one of them cost 99.99
Online on PC World web site, they were 59.99, 69.99, 79.99 and 89.99
It's money-grabbing mainly from business customers who may be desperate for same day or next day use (eg replacement printer for presentation, or as in your case, laptop charger when user will be on a business trip next day and needs charged laptop for train journey and while in business meeting at some client office).
I've never bothered to tell the staff, but feel as you do. Same with Maplins (which even has the nerve to charge about a fiver for their catalogue) but they are still going strong because they are easily visited by mugs business users who don't seem to know they are paying over the odds for most things.
If you check HotUKdeals.com you will now and then see web only or in-store bargains from Currys and Maplins but plenty more firms I'd do business with before either of them, unless the deal really looks good!
I guess (sweeping statement sorry) it doesn't matter so much if the cost goes onto an expense account, but it's the everyday customer who genuinely doesn't realise they're being ripped off that I feel sorry for.