In reply to Pyreneenemec: I’ve recently been through this; here’s my half peneth:
The recent trend towards using cyclo cross bikes for light n fast touring is well founded; but cross bikes have one or two disadvantages: race oriented bikes will have too narrow a gear ratio spread for touring being designed for races where the top speeds aren’t huge and steep climbs are done by carrying the bike. The handling will be nervous too, especially when loaded with luggage. And you won’t be able to put font panniers on many of them. Lastly the ride will likely not be exactly plush. That said, Ive just bought a Pinnacle Arkose from Evans and I’m very happy with it: great blend of speed and comfort. The Arkose is cross style but its really an audax wanabe with a bit of off-road capability so it suits my needs to a tee.
Second option is a traditional touring bike. Think Dawes Horizon or Ridgeback Voyage. Either would be much more like your Carlton than a cross bike, if only for the frame material, but with the added benefits of a comfy ride position and modern shifters n brakes. (Speaking of which, disc brakes may seem like overkill but I have them on both my mtb and roadbike and I wouldn’t go back to rim brakes if you paid me!) Another plus to a trad tourer is having a full set of braze ons for panniers etc; the bike’s geometry will also have been designed for riding with panniers which makes things much more pleasant when you’re loaded.
Whatever you buy make sure you can get tyres between 28 and 35mm wide on and still have clearance for mudguards.
Hope the above helps; anything more specific just ask n I’ll do my best to help.