Hello! Happy to offer a few suggestions: if you're looking to buy new, the Squier Classic Vibe series tend to come in south of £400, and are very well regarded guitars for the money. (And even the bog-standard Squier Affinity series are a bit more dependable these days - worth trying it out in a shop if you can, though!)
If you're willing to go down the rabbit-hole of second-hand models, there are plenty of Fenders floating around eBay, and it's worth keeping an eye on the marketplace boards, both here and over on Basschat (indeed, I bought my own Tele from a feller on Basschat). You can probably get your mitts on a Mexican Fender within the £400 limit; a US one might be more of a long shot.
It's also worth considering other brands' knock-off designs - some of them are thought to be better than their Fender namesakes! I see eBay has a couple of Tokai copies going in the low-300s, which have a good reputation. There's also a Schecter sitting at £239 right now - if it's anywhere near as good as my Schecter bass then you could be onto a winner there!