Nutritionally, there is no reason that a complete carnivore diet couldn't be produced for a snake, as it is for cats - although I suspect it would comprise of ground up rodent-based foodstuffs anyway.
However, I'm not aware of any that are on the market here in the UK - does anyone else know?
There are a brand called Reptilinks which are complete diets made for various reptiles including snakes. Only thing is they are not based in the UK and I'm not sure if they can be shipped as they need to be kept frozen until you need to use one. Have you ever considered getting an egg eating snake or garter snake? These are great species to keep if you're not keen on feeding mice. Egg eating snakes as their name suggests eats eggs such as quail eggs. Garter snakes eat Insects, and small fish
You're welcome. Depending on where you're located there's a few places to look for them :) There's Morph Market which is basically a website where reptile breeders can post what they have for sale. Majority of breeders on there do offer reptile courier where a registered animal courier will pick up the snake and drop them off at your house :) I'd also recommend having a look on Pets4Homes and Preloved (website or apps) as I've seen a few adverts for garter snakes on there located in Liverpool, Birmingham and Durham. Also have a look at your local reptile shops, I've noticed a fair few have started selling them now :)