At your price point [MENTION=4472]strings[/MENTION], owner of a B'Twin, radar has gone off, who are we to argue with him.
http://road.cc/content/news/72001-best-entry-level-road-bikes-under-£500
Hi
Yep, I've got a B'twin Triban 5, which has now been replaced by the Triban 500 model. I chose it, as it had Sora gears - slightly better than the basic 'Triban 3' model, and because it had a carbon fork.
I haven't done really big miles on it yet - partly due to a stupid rugby injury and partly due to becoming a father. Nevertheless, it effortlessly completed a sprint triathlon over the summer. The triple chainset - looked down on by many roadies - helped me fly up the climbs comparative to some other bikes.
I've just bought some proper Road shoes and want to ramp up the miles this year.
The downsides of the Triban range are the wheels, which I'll probably upgrade when I start on longer rides, and many Triban owners change the saddle (I've always found it comfortable, must have a funny shaped arse!).
I would recommend a trip to decathlon. The triban range are highly recommended at the price point, which is why I bought one. Decathlon may have something in the sale too.