Yamaha Guitars
I really like Yamaha acoustic guitars. If I had to buy a budget acoustic guitar without trying, I’d probably get a Yamaha. One of my current students has the Yamaha F310 (dreadnaught) acoustic guitar and it plays really nicely for its price point (around £120).
I’d personally recommend any acoustic guitar by Yamaha.
Eastcoast Guitars
Eastcoast Guitars are the new kid on the block when it comes to budget guitars. I’ve personally never tried one, but my old guitar teacher Justin Sandercoe now officially recommends them (he used to recommend Yamaha). If Justin recommends Eastcoast guitars they’re going to be great, and I’ll happily recommend them too. They also come in a variety of different size options at prices starting below £100.