Dawes Giro 500 Vs. Merida Road Ride 75 Vs GT GTR series 4

bonsaitiger Posts: 4
edited February 2011 in Road buying advice
I'm looking for a decent but budget road bike/tourer to do Lands End- JohnO'Groats on this summer for charity. My budget is £500 and I've seen these three advertised for around that mark or less. Has anyone got any advice on which of these would be most suitable, or if anyone has any suggestions about other possibilities that would be really helpful too!

Thanks guys.