I have two watches: One is a £20 Sekonda piece of junk, that gets worn for work. The other is a Rolex Datejust that was a 21st birthday present, that gets worn for special occasions.
Both look incredibly similar, and both tell the time. One weighs a crapload more than the other and is clearly better made, but other than that there's pretty much no difference between them when I'm wearing either. What I'm trying to get at I think is that, at your budget OP, I'd just be buying one that looks ace rather than worrying about quality. At £300 it's going to be of a certain standard, so get on the watch selling websites and just grab one you like the look of