Just to correct cookeaa, my Triban 3 came with carbon forks.
It’s my first road bike, so have nothing to compare it with, but it doesn’t seem a whole lot heavier than a riding buddies £1000 Trek. Ok so maybe the parts aren’t as good or high spec, but its a £300 bike.
It sounds like you’ve decided that if you do ride it a lot, you will be looking at a more expensive/higher spec bike next year in anyways, so why not save the money now, get the Triban 3, then you’ve got a nice winter bike if you do decide to get a new one next year.
If you find you’re not riding it very much, and hence won’t be getting a new one next year, then at £300, you’ve not maxxed out your budget on something you’re not riding much!