Too many variables as yet unanswered by the OP, but would suggest having a think about what’s most important in the tyres first, and what type of trails you’ll mainly be riding on.
If by winter tyre you mean something that’s a bit grippier than a summer tyre, and probably a bit slower rolling, then that’s one thing. If by winter tyre you mean you want full on narrow heavily spiked mud tyres, that’s another thing completely. But if you ride somewhere where it’s very soft year round, then you might actually want a full on mud tyre all year round too. If that makes sense?
And £50 for the pair, or £50 per tyre? Best thing to do is try and get a go on a few mates bikes, with different tyres on, or ask guys you ride with or see out on the trails, what they think of their tyres and why they like them. I’ve got my personal favourites, and I know why I like them and why I hate other tyres, but we’re all quite different and what suits me and my terrain may not suit you and yours so well!
Sorry, but it’s a BIG old can’o’worms on here the “what tyre” threads…