Well, it's an odd suggestion, but I've just bought a Carrera Subway One. The bike cost £198 (Sale price + 10% extra off for reserving online) and as I'm using it as a commuter, it's a bit low geared so I changed the cranks, cassette, front mech and BB for about £50. I put an 11-28 cassetee and a £20 Truvative chainset on with 28/38/48 rings
It's got all the braze ons you'll ever need, including front rack, it's a tough 7sp transmission, simple V-brakes and a solid MTB frame. Even the saddle is OK IMO. New racks and panniers, and a few other mods and you'll still have a NEW bike for under £400 all in, easy peasy.
It depends how your tour will go. I sold my Roadrat to get the Carerra, but only because I do a bit of offroad and it was battering the Cotic to bits. Too many punctures, too slow offroad.
If you'll be on smooth roads all the time, a Road Rat will be fine, but MTB wheels and 1.5in tyres are tougher and more comfy on rougher stuff.
I'm planning on touring Deveon and Cornwall on the Carerra next summer, towing a trailer, with Mrs PP on her Trek commuter. It'll be fine for that but I'll probaly stick the original 22/32/42 cranks and 12-32 cassette back on for that.
Something to bear in mind.
🙂