Thank me later.
Good advice. Also try www.herringshoes.co.uk - like Pediwear they always have some good offers, and are very helpful with enquiries. And www.meermin.es, but beware of some slow shipping sometimes, and check the various threads about fit.
Also, don't get a black boot. Black seems the most neutral, but it's actually the worst colour for versatility in a way, as it is hard to pair with casual stuff. Go for a darker brown, tan or burgundy, and it will work with everything from grey flannels to khaki chinos and blue jeans.