Where can i buy skyrim cheap? Phyiscal or Download version. (UK)

I'm looking to purchase skyrim for my switch as it one of my favourite games and i can play it on the go when out,ive looked at some stores and seen different prices.

Its currently £13 on this site for download but ive never used it before and wondering if anyone here can tell me if this site is trustworthy.

https://difmark.com/en/buy-console-account-the-elder-scrolls-v-skyrim-nintendo-36425?referal=keysforgames