So why do you need to change from the RC100?
Are you looking to go faster?
Do you want something more comfortable for riding several hours?
Or is this a social pressure "that's not very high end" thing?
I believe the bike industry is largely built upn selling people far more than they really need, at a far higher price than they need to pay. Remember, if your goal is exercise, and your only race is against the time that the same ride took you last weekend, then the 'better' the bike you buy, the fewer watts you expend every kilometre, and probably every hour.
But if you want greater comfort (I have no idea how good the Triban is for that) check your clothing; if you want greater smoothness, check your bike cleaning regime.
If you have really decided that you have set 1000EUR aside for this, and you are starting from scratch, then don't forget that the bike is only part of your outlay: unless you are already equipped, keep money back for shoes, helmet, clothing, maintainance tools and other essentials, then check what you have left for a bike.
You do not need the same brands and levels of gear that people doing rides of several times the duration, and at much higher speed, than you aspire to. Don't get sucked in to the ostentatiousness of so much of cycling culture.
A fool enthusiast and his money are soon parted.