I know this is a stupid question but....... I've seen a Dawes Galaxy 531 advertised locally. It states its a 25 and a half inch frame and would suit someone over six foot. I know the only way to know if a bike fits is to sit on it, but If its about the right size for the OH I'd buy it as a surprise for OH for his birthday, with a view to selling it on if its wrong - but i wont bother if it doesn't stand a chance of being right. Can anyone point me in the direction of a sizing guide for these bikes? Or just offer some advice?