Looks like a good bike, and very clean. Original saddle, and great spec. However, it does say it's a 64cm frame, which puts in in XL categories. Are you very tall with long legs? Ask the seller to make sure the 64cm bit isn't a typo, but the seatstays appear to suggest it is a bike for a basketball player..... (love that colour by the way!) If you are that tall, then it's worth a punt. It was a £1k bike new, so bid accordingly.... Detective work shows that the seller is a bike enthusiast, his purchase history tells us a lot about his cycling, and it all looks reassuring.
The Triban 3 has a strong fan-base on here. It is very well equipped with quality parts, and is incredible value for money. This year's model is a bit lower spec than last year, but still an excellent bike at the price point.